Fluctuating RPM at idle
#27
I have a similar problem:
The engine is several thousand km after rebuild and recently something like this happened:
The idle speed of the engine began to rise and fall with regularity exactly every second (it didn't seem random) by about 500 revs.
Even when I added gas and kept it at about 4000 rpm. it still happened with the same accuracy.
After less than minute it just stopped (not the engine
) and since then (+-300km) nothing like that happens.
Any ideas?
Should i be worried?
The engine is several thousand km after rebuild and recently something like this happened:
The idle speed of the engine began to rise and fall with regularity exactly every second (it didn't seem random) by about 500 revs.
Even when I added gas and kept it at about 4000 rpm. it still happened with the same accuracy.
After less than minute it just stopped (not the engine
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
Any ideas?
Should i be worried?
The following users liked this post:
Tomo (05-14-2023)
#29
40th anniversary Edition
I have a similar problem:
The engine is several thousand km after rebuild and recently something like this happened:
The idle speed of the engine began to rise and fall with regularity exactly every second (it didn't seem random) by about 500 revs.
Even when I added gas and kept it at about 4000 rpm. it still happened with the same accuracy.
After less than minute it just stopped (not the engine
) and since then (+-300km) nothing like that happens.
Any ideas?
Should i be worried?
The engine is several thousand km after rebuild and recently something like this happened:
The idle speed of the engine began to rise and fall with regularity exactly every second (it didn't seem random) by about 500 revs.
Even when I added gas and kept it at about 4000 rpm. it still happened with the same accuracy.
After less than minute it just stopped (not the engine
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
Any ideas?
Should i be worried?
- chokes as revs increase
- O2 sensor failure (too rich)
- MAF failure
- MAF disconnected
- e-shaft sensor fouled
- accessory belt fraying
- high end power loss (hard fuel cut)
- Rev limit reached
- high end power loss (jerky and stumbling)
- Ignition failure
- fuel pressure loss
- e-shaft sensor fouled
- high end power loss (smooth)
- Catalytic converter clog
- air filter clog
- low end power loss (smooth)
- Engine compression loss
- low end power loss (stumbles)
- Ignition failure
- front O2 sensor failure
- revs slowly but smoothly
- O2 sensor failure (too lean)
- catalytic converter clog
- air filter clog
- sudden power drop at a specific rpm
- Intake valving actuation problem
- trouble getting to redline
- Ignition failure
- front O2 sensor failure
- catalytic converter clog
- air filter clog
- e-shaft sensor fouled
- fuel pressure loss
- MAF failure
The following users liked this post:
wcs (05-15-2023)
#30
so I have the same issue as you it fluctuates from 750 maybe even lower sometimes back up to 100 to 1200. Would you recommend seafoam to help me with this issue? I have a gutted cat and sounds like an exhaust leak but I have exhaust leaks on my other cars and they never do this. Sorry for years late response but I just found this thread.
#32
Generating Power at Full Throttle
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Air Filter
• Intake Valving
• Throttle Body
• Mass Air Flow Sensor (MAF)
• Fuel Pump
• Fuel Injectors
• Catalytic Converter (Cat)
Keeping the Engine at a Cruise
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Intake Valving
• Throttle Body
• Mass Air Flow Sensor (MAF)
• Fuel Pump
• Fuel Injectors
• Front O2 sensor
• Catalytic Converter (Cat)
Keeping the Engine at an Idle
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Mass Air Flow Sensor (MAF)
• Front O2 sensor
• Catalytic Converter (Cat)
• Intake Vaccum
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Air Filter
• Intake Valving
• Throttle Body
• Mass Air Flow Sensor (MAF)
• Fuel Pump
• Fuel Injectors
• Catalytic Converter (Cat)
Keeping the Engine at a Cruise
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Intake Valving
• Throttle Body
• Mass Air Flow Sensor (MAF)
• Fuel Pump
• Fuel Injectors
• Front O2 sensor
• Catalytic Converter (Cat)
Keeping the Engine at an Idle
• Ignition Coils
• Spark Plugs
• Spark Plug Wires
• Engine Compression
• E-Shaft Sensor (ESS)
• Mass Air Flow Sensor (MAF)
• Front O2 sensor
• Catalytic Converter (Cat)
• Intake Vaccum
im having this issue and I hope I’m lucky I think it’s my cat since it is smelling like gas 24/7 my exhaust has a really bad rattle to it and it also take awhile to pick up speed.
The following users liked this post:
gwilliams6 (05-29-2023)
#34
I’ve had the coils wires a plugs changed for awhile, I’m still having idling issues, fluctuating from as low as 500 up too 1500 back and forth. I checked my solenoids for good connection my connectors are fine but idk if the solenoids are good. Anyway to check that without a voltmeter? Also air pump delete was done on this car as well. Comp is good seals are good engine was rebuilt. Just having these idle issues. Wonder if it’s a pcm problem. Guy before me says he went too have it tuned but doesn’t think the guy put a “real” tune on it. Somebody please help me
#35
40th anniversary Edition
I’ve had the coils wires a plugs changed for awhile, I’m still having idling issues, fluctuating from as low as 500 up too 1500 back and forth. I checked my solenoids for good connection my connectors are fine but idk if the solenoids are good. Anyway to check that without a voltmeter? Also air pump delete was done on this car as well. Comp is good seals are good engine was rebuilt. Just having these idle issues. Wonder if it’s a pcm problem. Guy before me says he went too have it tuned but doesn’t think the guy put a “real” tune on it. Somebody please help me
- chokes as revs increase
- O2 sensor failure (too rich)
- MAF failure
- MAF disconnected
- e-shaft sensor fouled
- accessory belt fraying
- high end power loss (hard fuel cut)
- Rev limit reached
- high end power loss (jerky and stumbling)
- Ignition failure
- fuel pressure loss
- e-shaft sensor fouled
- high end power loss (smooth)
- Catalytic converter clog
- air filter clog
- low end power loss (smooth)
- Engine compression loss
- low end power loss (stumbles)
- Ignition failure
- front O2 sensor failure
- revs slowly but smoothly
- O2 sensor failure (too lean)
- catalytic converter clog
- air filter clog
- sudden power drop at a specific rpm
- Intake valving actuation problem
- trouble getting to redline
- Ignition failure
- front O2 sensor failure
- catalytic converter clog
- air filter clog
- e-shaft sensor fouled
- fuel pressure loss
- MAF failure
- Starter
- Battery
- Engine Compression
- Grounding Wires
- Ignition Coils
- Spark Plugs
- Spark Plug Wires
- Fuel Pump
- Fuel Injectors
- Ignition Coils
- Spark Plugs
- Spark Plug Wires
- Engine Compression
- E-Shaft Sensor (ESS)
- Air Filter
- Intake Valving
- Throttle Body
- Mass Air Flow Sensor (MAF)
- Fuel Pump
- Fuel Injectors
- Catalytic Converter (Cat)
Keeping the Engine at a Cruise
- Ignition Coils
- Spark Plugs
- Spark Plug Wires
- Engine Compression
- E-Shaft Sensor (ESS)
- Intake Valving
- Throttle Body
- Mass Air Flow Sensor (MAF)
- Fuel Pump
- Fuel Injectors
- Front O2 sensor
- Catalytic Converter (Cat)
Keeping the Engine at an Idle
- Ignition Coils
- Spark Plugs
- Spark Plug Wires
- Engine Compression
- E-Shaft Sensor (ESS)
- Mass Air Flow Sensor (MAF)
- Front O2 sensor
- Catalytic Converter (Cat)
Last edited by gwilliams6; 11-27-2023 at 02:55 AM.
#36
Registered
Have you tried resetting the ECU. That’s what I did when my car was stalling out. Search for resetting the ECU; rx8club.com. do both ECU reset procedures (odometer reset button and brake pedal). Then, start the car. And without revving it, let it run for 20 minutes at idle. It will reprogram your idle. Hope it helps
Chad
Chad
Last edited by cmaderia10; 06-25-2024 at 02:56 PM.
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