N62B44 - Idle Surge - Jumpy Throttle at Idle Speed

[dkuchan]

Hey Guys,
I'm new to the forum, but I can't find any threads that seem to fit my problems so I figured I'd post.

I have a 2004 E53 with the 4.4 and my current problem is that I get idle surge but it's intermittent. I also have the intermittent issue where when I put the car in drive and touch the accelerator it will sometimes act as if there is a dead zone at the very beginning of pushing the pedal where nothing happens (it's a very small amount of pedal travel), but then when it responds the car lunges forward and it jerks (rpm's fluctuate) with the pedal if you hold it in that position where it first responds. This means that in a parking lot or driveway the car will lunge/surge at just above idle speed. When this is occurring I also have some problems with coasting RPM being too high which then appears to lead to downshifting issues. I also have a rough idle at times that will shake the car and it seems to come and go as well. These problems may all be related, but there isn't always a correlation between rough or surging idle at startup and the jumpy throttle response problem.

I had some low-end power issues as well, so I thought maybe the Vanos system was to blame for all these problems, but I replaced all 4 solenoids (with the genuine BMW solenoids) and these problems still linger. My low end power is better and the car does seem to run better so I did have some problem with the solenoids, it just wasn't the silver bullet I'd hoped it would be.

I am not throwing any codes.



Any ideas on what the root cause (or causes) might be? Any help is much appreciated.