SOLVED: 2003 X5, 3.0l, runs rough, reset on restart?

[cmelkoni]

Hello,

I know some of the symptoms I'm about to describe have been listed elsewhere in this forum, but I've been unable to find a description close to what I'm experiencing. If a solution is on another post, please feel free to direct me there.

Issue: Every so often, my X5 will run EXTREMELY rough, almost as if all cylinders are misfiring. No power, sputtering like crazy, etc. This only happens when the car is at idle and it doesn't matter if the car is warm or cold. It starts with a barely perceptible change in idle RPM then, upon stepping on the accelerator, the car sputters bad. Turning the ignition off, then right back on immediately solves the problem. Again, this always starts at an idle, not while driving. Example: I pull into a store parking lot the other day and sit with the car idling while checking my phone. RPM's drop from around 1000 to about 800 with a barely noticeable change in engine sound. I go to pull out and the engine is sputtering. I stop, shut the car off, and restart and everything is fine. The really strange part is the only code being thrown is a "Misfire, cylinder #2". Now, I've driven a car with 1 cylinder down before and it wasn't nearly as bad as what my X5 is doing. I can't believe that the sputtering that is happening is due to 1 cylinder misfiring, but I have been known to be wrong plenty of times before.

Here's what's been done recently: DISA valve rebuilt, spark plugs changed, intake boots and air filter checked. I just recently purchased this car and, when I changed the spark plugs, I saw evidence that someone had switched coils on Cylinder 1 & 2 in an effort to solve the issue.

Seems like an electrical problem over a vacuum issue because a restart of the car always fixes the problem.

Any help would be appreciated and, again, my apologies if this issue has been addressed elsewhere.