[Ruhnie]

Hoping to find someone that has heard of or seen this problem before. I have a 2007 335i with 65k miles on it. Sometime over the last year (I think, could be longer) I started noticing this weird stutter/fluctuation in power at RPMs < 2k. Once it really started to bother me, I paid more attention to it and can reliably repeat a "lurch" in power right at 2500 RPMs.

So I was looking for answers and ran into the myriad of threads about cleaning the intake valves. I had mine walnut blasted 2 days ago in hopes that it would resolve the issue. Unfortunately it did not (although the responsiveness overall is much better now). The shop actually mentioned to me that during the test drive they noticed the car seemed a little "soft" at low RPMs. They did some checks and could not identify any obvious leaks or visible issues that would case it. They are recommending a smoke test of some lines and/or replacing the vaccum lines. They also mentioned it could be related to the version of software the dealership put on the car back in May of 2011. I will probably just take it back to them and start going through these troubleshooting steps, but am hoping someone around here has a more definitive idea. Any input is much appreciated.