4.4i M62 Rough Idle - No Codes!

[seanbreaux]

Hi All,

I have had a persistent rough idle for a long time now on my 2003 e53 4.4i M62 and can't figure out the cause. No Codes! At idle/low RPMs the engine is quite rough and the RPMs bounce when the RPMs drop (for instance when coming to a stop sign). If I drive the car hard for a long period of time the rough idle drastically improves until I turn the car off and let the engine go cold. In the mornings though the idle is really rough and on most normal trips the idle is rough the entire time. If I turn the AC on and raise the RPMs the rough idle is lessened. At higher RPMs the car runs beautifully. Here is what I have done so far.

- PCV valve and gasket on rear of intake.
- Oil separator and new hoses
- Intake gaskets on front of intake.
- Just did the valley pan and replaced intake gaskets underneath manifold
- O2 sensors replaced
- New MAF
- Valve Cover Gaskets

I have not smoked the engine after replacing the above and is the only thing I can think of next to do. Does anyone have any other suggestions? I keep hearing VANOS can cause rough idle as well which I have not addressed. Thoughts?

Sean