I removed WBO2 sensor from pipe and let dangle in fresh air. Holley EFI; Sniper EFI; If this is your first visit, ension-Harness (WBO2 Sensor Test At End Of Wideband O2 Sensor Notes) May Gods grace bless you in the Lord Jesus Christ. 67 Part# 558-443 Add To Cart Hooker BlackHeart Oxygen Sensor O2 Bung 2. An oxygen sensor does not have to fail completely to give you problems. Typically, labor costs for a sensor replacement are around $150. 02 sensors are very heat sensitive, and can detect an exhaust pulsation in a single Header tube, thats why we always wanted to position the sensor into at least 2 opposite firing tubes we running Headers. Holley Sniper O2 sensor replacement. I also noticed the Sniper trying to run more lean in these moments than normal (like 15. Sniper EFI Installation Tips from Holleys Tom Kise>Top 10 Sniper EFI Installation Tips from Holleys Tom Kise. When it’s up & going it runs smooth but just getting there is a hassle. Especially obvious when it cant idle. Dont know how smart they are but thats a safety feature from high pressure pump EFI day 1: no CPS RPM detected, no fuel pump relay power after 2-3 seconds. Unit will still read but accuracy may be impacted. It’s seems to be doing it quite often. My firm guess is that they dont and will find be a much cheaper alternative. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. Your car may run sluggish and rough, with. Pay specific attention to the O2 sensor cable lead. Any ideas on where I should go next if the O2 sensor doesnt help? Coolant sensor? Of do I have to start posting my data logs on the Holley Forum??. Looking down throat of the TB, with butterflies open, the intake was soaked with gas, and the small vent at rear, top of TB was showing that smokey look, like a carb would do when say you had a stuck float, and the engine was badly flooded Thats also how it was running. On the contrary, even a failing O2 sensor (sometimes called a “lazy” O2 sensor) may cause. worked fine while idling and driving harder. It is possible for the ECU to have an internal failure that can kill O2 sensors. Holley EFI Wbo2 Sensor, Sniper Tbi Brand: Holley 43 ratings $13295 Available at a lower price from other sellers that may not offer free Prime shipping. Ive gone through a bunch of the Holley 02 sensors and at $240. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. Tested my o2 sensors and determined the ECU on my Holley Sniper Efi is bad. If you datalog the Sniper ECU and see multiple overlapping traces for the same signal, you likely have RF-induced problems. Troubleshooting Holley Sniper that hesitates on acceleration. The nature of the hesitation feels more like gas than spark. When you need to service your Sniper EFI throttle body, Holleys list of parts include these O2 sensors to maintain a proper reading of oxygen levels in the exhaust. The owner is frustrated because the engine is running way. Common Check Engine Light Causes: Oxygen Sensor. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 >Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000. This ensures that the O2 sensor takes its measurements after the exhaust gas from each primary merges into a common collector. Holley Oxygen Sensor O2 Bung Weld-In Style. Discussion Starter · #7 · Jun 3, 2016. Red Unplugd UnP Sensor is unplugged. You may also notice reduced fuel economy, and the car may. Also the closer the O2 to the engine, the quicker the O2 heats up to give a reading on a cold start. The distance to the O2 sensor impacts the response time. I reinstalled sensor turned Closed Loop & Learn off and restarted truck. Wideband Realities: The Truth About Oxygen Sensors …. Additionally, if an Sniper or Terminator X EFI System has repeated O2 sensor failures and none of the above-listed suggestions seem likely then contact Holley and arrange to have the unit tested. So, what are the symptoms of a bad O2 sensor? Here are 10 common bad oxygen sensor symptoms: Continually failed emission tests Flashing or illuminated CEL ( Check Engine Light) Misfiring, rough idling, or stalling Bad fuel economy/ gas mileage Poor engine performance Engine noises Black exhaust fumes Sulfuric/rotten-egg smell from the exhaust. PDF Sensor Diagnostics and Statuses. I was just hoping for some feedback before sitting on the phone waiting for tech support. On the contrary, even a failing O2 sensor (sometimes called a “lazy” O2 sensor) may cause your car to have a few issues. 74K subscribers Subscribe 14K views 3 years ago Attempted to make a parts run in my 1990 Third gen. Bad Oxygen Sensor (O2) Symptoms & Replacement …. Looking down throat of the TB, with butterflies open, the intake was soaked with gas, and the small vent at rear, top of TB was showing that smokey look, like a carb would do when say you had a stuck float, and the engine was badly flooded Thats also how it was running. Top 10 Sniper EFI Installation Tips from Holleys Tom …. The ECU controls the fuel mixture, idle speed, ignition timing, and in some cases, valve timing, and drive-by-wire throttle-body if so equipped. It needs the tip pointed down at least 10 degrees from horizontal and at least 15 degrees from vertical I prefer. Yellow Hot! Hot Sensor is above calibrated operating temperature. Fine tuned the timing to 12-15 degrees. These replacement Bosch wideband sensors feature anti-seize pre-applied to sensor. In summary, below are 10 common bad oxygen sensor symptoms: Continually failed emission tests; Flashing or illuminated CEL (Check Engine Light) Misfiring, rough. One of the reasons is that OEM EFI systems are constantly testing the engine. Symptoms Of A Bad Oxygen Sensor And Replacement Cost>8 Symptoms Of A Bad Oxygen Sensor And Replacement Cost. 4K views 9 months ago This is my 1959 Ford F100 that. WBO2 Sensor 17025 Bosch 554. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. If your cars oxygen sensor is faulty, it can cause a number of problems. #4 · Oct 13, 2022 My O2 sensor issues were determined to be the sensor tip being to deep into the exhaust pipe. We double checked all wiring, no exhaust leaks, etc. LED PC Text Gauge Text Description None Disabld … Signifies that sensor channel is not enabled. This ensures that the O2 sensor takes its measurements after the exhaust gas from each primary merges into a common collector. 9 fits AEM Holley Sniper Terminator X 4 product ratings Condition: New Compatibility: See compatible vehicles Quantity: 6 available 21 sold / See feedback Price: US $79. #4 · Oct 13, 2022 My O2 sensor issues were determined to be the sensor tip being to deep into the exhaust pipe. From startup the AFR is sky high and visibly pumping fuel and smoke out. If your cars oxygen sensor is faulty, it can cause a number of problems. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. Once you have the tune done, then close the params to 5% or so just in case you do have a wideband issue, or even a misfire due to a bad plug wire. No Start Condition Engine Runs Poorly at Operating Temp Erratic Idle Condition Incorrect Fuel Pressure Magnetic Distributor Timing Control Setting Crank Reference Angle to 45°. Subscribe 13K views 3 years ago Tested my o2 sensors and determined the ECU on my Holley Sniper Efi is bad. How To Check Your O2 Sensor At Home. Last summer, a faulty ECU in my Holley Sniper EFI took out my 1972 Ford Mustang, bringing it into early storage for winter. Holley EFI Oxygen Sensor. Holley Sniper Issue solved and a tip that might help. As your oxygen sensor is going bad you may notice your vehicle is running rough, misfiring or running irregularly while idling. It has been a month and the light hasnt come back on. The oxygen sensor is a critical component of any electronic engine management system, and relays real-time air fuel mixture data to the computer for minute adjustments to fuel mixture. Add to Wish List Service Oxygen Sensor for Sniper EFI Systems;. I know from some of the other posts, there have been WBO2 sensor issues. I was just hoping for some feedback before sitting on. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 miles. The first thing you should do when you suspect that you have RF interference is. 22 Part# 543-120 Add To Cart Holley EFI CAN to USB Dongle - Communication Cable $65. 74K subscribers Subscribe 14K views 3 years ago Attempted to make a parts run in my 1990 Third gen Chevy Camaro with a small block chevy. Holley Sniper EFI oxygen sensors are the best replacements for your system. In one of the other posts someone said they used the Bosch 17025 LSU4. This one came in with black clouds and 100% fuel Learn on the handheld barely running, with the WBO2 reading at 35:1 AFR. O2 Sensor Mounting: The O2 needs to be mounted 6-8” after the merge in the header collector. my bad Holley bosch sensor had similar surge spot under light throttle. Holley Sniper EFI Oxygen Sensors 554. Anyone have a good place to find a genuine Bosch O2 replacement sensor without paying $110?. Long story short, I managed to delete the current file and replace it with the current FW: tslcd35st_sniper_fw_01_03_0500. Bosch 17212 Wideband Oxygen O2 Sensor LSU4. The O2 sensor is not a passive sensor that simply sends back data. This video could save you hours of time on the dyno. Holley Sniper EFI oxygen sensors are the best replacements for your system. The harnesses are long enough to mount into. From startup the AFR is sky high and visibly pumping fuel and smoke out. One of the reasons is that OEM EFI systems are constantly testing the engine. O2 Sensor Mounting: The O2 needs to be mounted 6-8” after the merge in the header collector. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. Solving RF Interference Issues in Sniper Installations. Watch this short video that will give you tell tale signs to look out for if your tune suddenly runs rich or lean. This price, of course, varies from vehicle to vehicle. Many sensors, nonetheless, cost between $20 and $100. Wideband Realities: The Truth About Oxygen Sensors. Also, with Headers you loose 600 to 700 degrees between Head and bottom collector, you dont want to read that loss. An excessively rich condition & ignition misfires will cause the WBO2 sensor to read falsely lean. 9K subscribers Subscribe 25 Share 2. If you notice any of the following signs, you may have a bad O2 sensor or one that is about to go bad:. An excessively rich condition & ignition misfires will cause the WBO2 sensor to read falsely lean. 67 Part# 558-443 Add To Cart Hooker BlackHeart Oxygen Sensor O2 Bung 2. Featured Products EFI - Fuel Injection $2. If you leave a bad oxygen sensor in your car for several months, it may cause serious damage to the engine and catalytic converter. Not much changed it, restarting, idle, full throttle. The oxygen sensor is a critical component of any electronic engine management system, and relays real-time air fuel mixture data to the computer for minute adjustments to fuel mixture. The potential issues could be a vacuum leak, ignition system, or something similar. It can also lead to high pollution levels. This minimizes installation time and packages really well on a diverse group of engine applications. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. However, now that we have the Sniper back, it is time to get the car. got worse pretty quick sensor showed 35. Sensor Diagnostics and Statuses. Holley Performance >Changed mufflers, now 35. I bought a new holley sniper , dual sync dist. Subscribe 13K views 3 years ago Tested my o2 sensors and determined the ECU on my Holley Sniper Efi is bad. Yellow Cold! Cld Sensor is below calibrated operating temperature. Holley efi behavior with bad o2 sensor, safety feature>Holley efi behavior with bad o2 sensor, safety feature. Yellow Heating HO Sensor is heating. Anyone have a good place to find a genuine Bosch O2 replacement sensor without paying $110? Sponsored Links (REGISTERED USERS DO NOT SEE THIS POST/AD! Register now for free!) Advertising. 6 afrs when it cutted out and compensation added tons of fuel to it and made engine sputter and stall. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. An oxygen sensor does not have to fail completely to give you problems. I have a feeling there is an issue inside the unit. A N/A engine is a lot harder to hurt than a power-adder engine, except for high-rpm and high-compression stuff. Holley sniper failure, this time its all bad. The Holley sensor took a few minutes to start working again, because of all the soot, but it came back to life. What O2 sensor does Holley sniper use? Not only does the AEM fit 9 Holley Sniper, but it also fits the Terminator X. Holley Sniper EFI troubleshooting: Bad ECU??. my bad Holley bosch sensor had similar surge spot under light throttle. Yellow Cold! Cld Sensor is below calibrated operating temperature. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. 10 Bad O2 Sensor Symptoms (What to Look Out For). Featured Products Holley EFI NTK Wideband Oxygen Sensor $318. Seems the Sniper should have a fail safe if it sees the rail pressure drop with an RPM (NONE) mismatch. Holley part number 554-155. Wideband Oxygen Sensor Status Shows status of wideband oxygen sensors. Yellow Heating HO Sensor is heating. It needs the tip pointed down at least 10 degrees from horizontal and at least 15 degrees from vertical I prefer about a 45 degree angle from horizontal. Sniper EFI Releases new Stealth 4150 Models! Staff. Share 02-13-2006, 10:36 AM #8 adham Member. - Fuel pressure has been verified at the Sniper EFI throttle body and is between 55 & 65 psi - All wiring has been tied away from potential hazards such as the exhaust, fans, pulleys, spark plug wires, 12 Volt accessory wires, the ignition coil and ignition coil wiring. Free Shipping - Lower 48 US States. If ignition is turned on and the engine is not started, after a period of time, the AFR will start reading “Init…” until the Sniper EFI ECU sees an RPM signal. It is possible for the ECU to have an internal failure that can kill O2 sensors. It can also lead to high pollution. If your cars oxygen sensor is faulty, it can cause a number of problems. About this item Genuine Holley Quality Parts Corrosion resistant Made from quality materials Easy installation Durable and long lasting › See more product details Frequently bought together +. Sniper EFI Coolant Temperature Sensor: $26. Symptoms of RF Interference in Sniper ECUs The first thing to realize is that RF interference can manifest itself in ways that will have you suspecting and replacing everything in the system. Additionally, if an Sniper or Terminator X EFI System has repeated O2 sensor failures and none of the above-listed suggestions seem likely then contact Holley and arrange to have the unit tested. You may also observe other engine performance problems, such as loss of power, hesitation, or stalling. Symptoms of RF Interference in Sniper ECUs The first thing to realize is that RF interference can manifest itself in ways that will have you suspecting and replacing everything in the system. To Properly Place and Install an O2 Sensor. It must be actively driven and controlled by the ECU. 1 Syleng1 Karma is real and Life is short FABO Gold Member Joined Jul 5, 2005 Messages. Sniper EFI Coolant Temperature Sensor: $26. Holley Sniper Bad O2 Sensor SymptomsSeems the Sniper should have a fail safe if it sees the rail pressure drop with an RPM (NONE) mismatch. When you need to service your Sniper EFI throttle body, Holleys list of parts include these O2 sensors to maintain a proper reading of oxygen levels in the exhaust. Obviously, if the O2 sensor did not respond properly then it is bad and will need to be replaced. Its sort of like vapor lock, but I drove this car for three years in Texas summers with no issues. Fine tuned the timing to 12-15 degrees. Watch this short video that will give you tell tale signs to look out for if your tune suddenly runs rich or lean. If you have any exhaust leaks between the combustion chamber and 18-24” after the sensor you are going to have problems. Using a timing light for misfire detection works well (watch for a consistently flashing strobe light). Check Engine Light Illuminates. If you have any exhaust leaks between the combustion chamber and 18-24” after the sensor you are going to have problems. - Fuel pressure has been verified at the Sniper EFI throttle body and is between 55 & 65 psi - All wiring has been tied away from potential hazards such as the exhaust, fans, pulleys, spark plug wires, 12 Volt accessory wires, the ignition coil and ignition coil wiring. The best way to describe the symptoms is that at light throttle (<10% TPS) theres a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. O2 Sensor Mounting: The O2 needs to be mounted 6-8” after the merge in the header collector. Holley Sniper Bad ECU FINALLY FIXED!. Sniper Bogging. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000. Sponsored Links 09-27-2020, 10:39 PM. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. Symptoms of a Bad or Failing Oxygen Sensor. This car runs on methanol, and at the track the last couple outtings the car was misbehaving and reading really rich. I ended up disconnecting the WBO2 sensor to get it to run and back home. Those engines are still tough to hurt, except for detonation issues. Crankshaft position sensors allow the ECU to interpret how fast the engine is spinning and where it is at in its rotation. Im sure the front O2s are completely clogged possibly giving me a rich condition. Replacement Sniper and Terminator X O2 Sensor. 99 Add to cart Add to Watchlist 1-year accident protection plan from Allstate - $10. The nature of the hesitation feels more like gas than spark. If you notice any of the following signs, you may have a bad O2 sensor or one that is about to go bad: An illuminated check-engine light A rough engine idle A misfiring engine Worsening fuel economy Failed emissions inspection. worked fine while idling and driving harder. This ensures that the O2 sensor takes its measurements after the exhaust gas from each primary merges into a common collector. An excessively rich condition & ignition misfires will cause the WBO2 sensor to read falsely lean. So I spraying it down with carb cleaner trying to shoot it in the slits. Displayed so quickly you likely do not see this. I happen to have a box of them here, as I use them on the dyno for tuning. This allowed moisture and cold cranking fuel to contaminate (soak) heating element causing premature failure during cranking and idling. 15 Part# 71014302-RHKR Add To Cart Holley EFI Terminator X Wideband Adapter Harness $47. 95 2129 Products View Parts Sensors. The most typical culprits are the spark plug and coil wires. The best way to describe the symptoms is that at light throttle (<10% TPS) there’s a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. Bad Oxygen Sensor (O2) Symptoms & Replacement Cost. If the O2 sensor fails to respond correctly to the lean and rich fuel tests, another component could be causing the problem. bad o2 sensors=power loss?. Holley EFI Oxygen Sensor. Bad Oxygen Sensor? Holley NTK. Have you tried manually tuning the idle in Open Loop? (Disable Closed Loop in System Parameters. Pinched or Burnt O2 sensor Wiring: Keep it high, tight, and safe. Since I replaced the O2 about a year ago I figured what the hell, lets try to clean it. 00 a pop Im going to figure out if they need to cost what they do from Holley. Holley Oxygen Sensor O2 Bung Weld-In Style. Positioning the sensor too close to the exhaust ports can expose it to high exhaust gas temperature (EGT) as well as over-cooling from the high-velocity exhaust gas flowing over the sensor. 22 Part# 543-120 Add To Cart Holley EFI CAN to USB Dongle - Communication Cable $65. Your mechanics labor costs also likely vary based on a few factors, including how difficult it is to access your sensors. Holley Sniper O2 sensor replacement. It will lean a cylinder out and watch for the O2 to change. 5 AFR instead of high 13s or low 14s). Once you have the tune done, then close the params to 5% or so just in case you do have a wideband issue, or even a misfire due to a bad plug wire. Here is a more detailed list of the bad oxygen sensor symptoms: 1. Additionally, if an Sniper or Terminator X EFI System has repeated O2 sensor failures and none of the above-listed suggestions seem likely then contact Holley and arrange to have the unit tested. Once you have the tune done, then close the params to 5% or so just in case you do have a wideband issue, or even a misfire due to a bad plug wire. Long story short, I managed to delete the current file and replace it with the current FW: tslcd35st_sniper_fw_01_03_0500. I also noticed the Sniper trying to run more lean in these moments than normal (like 15. 02 sensors are very heat sensitive, and can detect an exhaust pulsation in a single Header tube, thats why we always wanted to position the sensor into at least 2 opposite firing tubes we running Headers. 95 Part# 554-100 Add To Cart Holley EFI LSU4 Bosch Wideband $194. Yellow Init… In First shown for an instant when the system is powered on. Holley EFI Wbo2 Sensor, Sniper Tbi Brand: Holley 43 ratings $13295 Available at a lower price from other sellers that may not offer free Prime shipping. The Sniper EFI unit only requires four wiring connections: battery positive and negative; a key-on, 12-volt source; a crank signal; and an rpm signal. The most common bad oxygen sensor symptoms are poor engine performance and rough idle, along with a check engine light on your dashboard. Symptoms of RF Interference in Sniper ECUs. Since it was reading rich, the compute. It uses the sensors to monitor specific engine parameters and make changes to those based on the information it is receiving about the engine’s operating conditions. I ended up disconnecting the WBO2 sensor to get it to run and back home. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 miles. 95 Part# 554-101 Add To Cart Holley EFI Oxygen Sensor. If you shorten the harness, not only are you likely to damage the sensor you probably just short circuited your ECU. Discussion Starter · #7 · Jun 3, 2016. Common Check Engine Light Causes: Oxygen Sensor. Explained: Holley EFI Sensors and What They Do. So, its important to keep an eye out for symptoms of a bad oxygen sensor and fix it as soon as possible. On EFI systems such as Holleys Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. O2 sensor failure on a Holley Sniper EFI Zanes Garage 4. car is a third gen 1990 Chevy Camaro with flowmaster mufflers. 18 Part# 558-463 Add To Cart Earls. On EFI systems such as Holleys Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. RPM going up and down , miss firing and. O2 sensor placement is critical for getting your engine to read the oxygen in the exhaust correctly and can directly impact the performance of your new EFI installation. This fixed the high throttle position sensor reading (TPS) of above 1% that likely caused my idle issues. On the contrary, even a failing O2 sensor (sometimes called a “lazy” O2 sensor) may cause your car to have a few issues. On EFI systems such as Holleys Sniper, all of the EFI sensors (except for the O2 and coolant temperature sender) are mounted snuggly in the throttle body. 8 to 12 AFR and it does fluctuate/move, I can rev the engine and hold RPM, and WBO2 reads 14 then goes back to 12. O2 sensor placement is critical for getting your engine to read the oxygen in the exhaust correctly and can directly impact the performance of your new EFI installation. Holley Sniper Issue solved and a tip that might help>Holley Sniper Issue solved and a tip that might help. locating an O2 sensor in a side pipe. Started truck and WBO2 sensor showed 23 AFR. The owner is frustrated because the engine is running way too rich, fouling plugs, and generally runs poorly. Replacement Sniper and Terminator X O2 Sensor. If ignition is turned on and the engine is not started, after a period of time, the AFR will start reading “Init…” until the Sniper EFI ECU sees an RPM signal. 4K views 9 months ago This is my 1959 Ford F100 that I’ve had. You should then have at least 18-24” of pipe after the sensor. 2 block, forged steel crankshaft & H-beam rods, forged pistons, Trick Flow Twisted Wedge 11R 205 CNC. In summary, below are 10 common bad oxygen sensor symptoms: Continually failed emission tests; Flashing or illuminated CEL (Check Engine Light) Misfiring, rough idling, or stalling; Bad fuel economy/gas mileage; Poor engine performance; Engine noises; Black exhaust fumes; Sulfuric/rotten-egg smell from the exhaust; Sudden catalytic converter. The best way to describe the symptoms is that at light throttle (<10% TPS) there’s a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. Here is a more detailed list of the bad oxygen sensor symptoms: 1. You may also notice reduced fuel economy, and the car may fail an emissions inspection. I removed WBO2 sensor from pipe and let dangle in fresh air. Yellow Heating HO Sensor is heating. Sniper EFI Coolant Temperature Sensor: $26. All engine compartments have a bounty of sources for RF noise. Installed a Lokar throttle linkage bracket custom made for the Sniper, removing the old one that had been on my Holley 750. Your car may run sluggish and rough, with stalls, and poor fuel efficiency. When I go to throttle to get up on the plain a lot of the time it struggles to get full revs so I back it off and try again and then it’ll get full power. These replacement Bosch wideband sensors feature anti-seize pre-applied to sensor threads. After about 15-30 restarts, the engine is now running excessively rich and yet the O 2 sensor still detects free oxygen present in the exhaust. Nothing is burnt through, or disconnected. my bad Holley bosch sensor had similar surge spot under light throttle. I also noticed the Sniper trying. Since I replaced the O2 about a year ago I figured what the hell, lets try to clean it. Holley Sniper that hesitates on acceleration>Troubleshooting Holley Sniper that hesitates on acceleration. , coil, and holley in tank fuel pump, When engine got hot it would go crazy. Holley Sniper EFI O2 Sensors Keep Failing! 3rd one in 1,000 miles. Knowing what all the moving parts inside and. if it suddenly goes leanyou know the sensor is bad if after a minute its still pegged rich, the sensor is good This test works with ANY o2 sensor Click to expand Back in the 20th century , I used a DMM that read frequency and looked for 5Hz or over for a good sensor in closed loop with the sensor good and warm at a fast idle. suspect bad o2 sensor with Holley efi. Positioning the sensor too close to the exhaust ports can expose it to high exhaust gas temperature (EGT) as well as over-cooling from the high-velocity exhaust gas flowing over the sensor. The best way to describe the symptoms is that at light throttle (<10% TPS) there’s a significant power loss, engine stumbles making the car lurch, and a very unhappy rough exhaust sound almost like a Jake Brake. The Holley sensor took a few minutes to start working again, because of all the soot, but it came back to life.