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Hello, my car occasionally has rpm fluctuations on idle, especially when the engine is cold. I don't notice any power loss or fluctuations of some sort while driving.
I've included a link to a video showing one of the worst occurrences. After reading a few threads on the topic, they suggest that it could be the HPFP, which I doubt is the issue now because I've already had it replaced. It could also be the torque converter, but I'm not sure how to diagnose that. Another possibility could be related to the air system but I can't exactly point out which part is failing.
It would be great if I could get some insight into the situation.
I vote for your AIR LEAK suggestion.
Definitely not torque converter....
At 230,000Km, everything's possible!
Before swapping more parts you want to SCAN your car for active faults. The scanner will also provide you will fuel pressure data. The way rpm is surging super regularly sorts of rules out a gas issue.
What I think is going on is the ECU is not satisfied with the air intake sensor (MAF/MAP). The ECU is ramping with the idle to test for valid data.
I vote for your AIR LEAK suggestion.
Definitely not torque converter....
At 230,000Km, everything's possible!
Before swapping more parts you want to SCAN your car for active faults. The scanner will also provide you will fuel pressure data. The way rpm is surging super regularly sorts of rules out a gas issue.
What I think is going on is the ECU is not satisfied with the air intake sensor (MAF/MAP). The ECU is ramping with the idle to test for valid data.
Practically...:
scan early, scan often!!
check there's no intake air leaks
clean intake sensor
watch live data output under suspicion
✌️
Thank for your suggestion. I took your advise and cleaned both the MAF and throttle body. The car idles more stable now. However, I did compare the air mass flow rate before and after to see whether there was a difference but both readings came out the same, around 18-19 kg/h. Shouldn't it make a much lower reading after cleaning the sensor?
Hi,
I had issue with rough ideal during morning time, no transmission jerking it was serviced with oil change from dealer. I used diesel purge in tank of 5 liters of fuel and replaced new fuel filter. No more jerking from last 6 months. Attached pic of 1.5 year old fuel filter condition which was removed.
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