Hey guys,

I need some help. A few days ago my car threw a CEL that says P0171 Running Lean and my car is also whistling loud during low RPMS (2000-4000). It also gave me the ENGINE MALFUNCTION iDrive error. I thought that the MAF was dirty and I cleaned it. Doing that made the car run slightly better but still shudders and whistles. Could it be a bad o2 sensor or hidden vaccum leak? I also tried spraying starter fluid in the engine bay to no avail on finding a leak.. I'm at loss for what the problem is.

Any ideas? I figured this may be a common problem. My car is a 2008 528i with 110k

I cleared the CEL with INPA before I went to bed last night and the ENGINE MALFUNCTION came back this morning when I started it up.

Thanks for any help anyone can provide.