Need advice (N54)

[seano643]

I drive a 2008 E90 335i. A few months ago I began to have a rough idle on cold starts and the car got to the point where it would want to stall out. I was at school about 3 hours away from home at the time. It was an on and off type of thing every day or so. I ended up making it home for winter break and first thing we found was misfire in cylinder three. Fixed that issue, replaced spark plugs and coil packs and everything was fine.

I came back to school in the beginning of January and everything was fine but the second day I am back the issue starts again but slightly worse. The car had irregular, long crank times straight into a very rough idle that shook the car violently. The car rough idles around 1250 rpms and then falls down under 500 rpms (sometimes around 250) and gets to the point where it is going to stall out. It sounds as if it is starving for fuel at this point which is obviously leading me to believe that it is fuel system issues. Leaky injectors, clogged fuel filter or something along these lines. I have also been wondering if it could be a sensor somewhere in the system. The car has not thrown me any hard codes so I am wondering if it could be giving shadow codes that I won't be able to see here because I do not have my code reader with me at school.

If anybody has had the same issue and found the resolution I would gladly appreciate a comment back or some advice of where to start with limited time and tools.

[MarcoZandrini]

The first step in diagnosing a problem is to scan the engine computer (DME) for codes. The Service Engine Soon light is on only when an emissions related code is present. I recommend the OBDFusion app for your smartphone or tablet. You’ll need a communications adapter that plugs into the obd2 port under the dash. WiFi is recommended for iOS. Bluetooth is recommended for android. Search this forum fir threads on the app.