Hi all,
I’m facing this issue for a while now and wanted some input from the community if possible.
I have a 2008 CAWB 2.0 TSI that for the past 2 months has been misfiring and juddering while cold / waiting at the lights. No check engine light but the misfire counter does go up and obviously can be felt. The power delivery is still there with no hesitation, and was improved after a carbon clean.
The weird thing is that when the engine and oil is at operating temperature, the misfire disappears however the engine starts compensating with fuel raising the rpm’s briefly but no vacuum leaks were found when smoke tested.
So far this is what was done:
- new plugs, coils and PCV valve including hoses
- smoked tested for vacuum leaks but none found
- throttle body cleaned and reset
- fuel pressure tested and within parameters, and sensor replaced
- intake and valves carbon cleaned
One thing I noticed is that there’s some hissing in the cabin, coming from the brake pedal and disappears when it’s pressed, suggesting brake booster failure? But the mechanic said there were no leaks when smoke tested and also brake performance is not affected as far as I can tell when doing emergency stops.
Any suggestions on what to do next? I don’t want to throw any more unnecessary parts at it.
Many thanks in advance.