[Hotter]

Hi, my BMW 328i N52 is having rough idle, vibrating seat/steering wheel. Also engine startup is a bit rough too.

I thought vibrations were due to valve cover oil leak (I thought maybe that causes vacuum leak), but changing valve cover/gasket and fixing this oil leak did not help.

Additionally I have changed spark plugs, MAF, front engine mounts, but that did not help either.

It seems that tachometer show idle ~580 (I believe previously when everything was ok it was showing higher idle at exactly 600) even though INPA is showing idle at ~650.

It has rough startup and vibrates on both hot/cold engine. When driving engine is smooth, no issues.

Could it be vacuum leak? I tried disconnecting MAF, it seems that it does not change much, engine is running similarly. So could I do an assumption that its not vacuum leak?

How could I diagnose if its fuel injectors?

Any other ideas?

Currently I just increased RPM so it idles smoother, but I would like to find the root cause.