[Semaj07]

Hey all!

I have a 2014 328i XDrive and it is stock. Recently, the car had been having some engine stumbling on a cold start. I went and cleaned the MAF sensor and that seemed to help. However, while I had been searching for the rpm stumble, it actually threw a p0172 code. My LTFT were too high. After I cleaned the maf the code never came back, HOWEVER the LTFT numbers are still not right. They are around -15 through -20. Car seems to be running ok and I did replace the spark plugs just today and the upstream o2 sensor thinking that could be the culprit. I figured both were good to do but did nothing it seems lol. Vehicle has 76k miles on it. Any help would be great because I’m not sure where to go from here. Thanks!!

[Maverickoso]

Run the car from idle from cold for maybe 1 minute and then shut off. Check your plugs to see if any are gasoline soaked or just smell of it. Although I didn't check any my fuel trims, when I got my car, plugs were just the first thing I wanted to check out. Cylinder 4 had a light gasoline smell. Slightly leaking injector. Ended up getting one cheap from Rock Auto and then the local stealership to get a new coupler ring.

Even with cleaning your maf, your maf may be shot. I loathed troubleshooting high negative fuel trims on past turbo cars. If at idle, boost leaks, vacuum leaks will give you such numbers.

[Semaj07]

Thanks for the response! I’ll definitely give that a shot. What’s interesting to me is if it’s a leaking injector would it still show high values while driving? Even while driving it’s consistently between -15 and -20.

[hayawan]

I'm having the same issue 2012 328i (f30) running rich, what was the fix for your car? Both my long and short fuel trim levels are -30 I'm suspecting the HPFP is dumping fuel in the crankcase but I don't smell any fuel when I open the oil cap immediately after shutting the car off.

[Romy]

Originally Posted by Semaj07

Hey all!

I have a 2014 328i XDrive and it is stock. Recently, the car had been having some engine stumbling on a cold start. I went and cleaned the MAF sensor and that seemed to help. However, while I had been searching for the rpm stumble, it actually threw a p0172 code. My LTFT were too high. After I cleaned the maf the code never came back, HOWEVER the LTFT numbers are still not right. They are around -15 through -20. Car seems to be running ok and I did replace the spark plugs just today and the upstream o2 sensor thinking that could be the culprit. I figured both were good to do but did nothing it seems lol. Vehicle has 76k miles on it. Any help would be great because I’m not sure where to go from here. Thanks!!

Did you fix it? I’m going thru the same prob- -14ltft.