Rough acceleration with check engine light under heavy acceleration

[Doc T]

Hey all! I have a 1999 328i sport with 102000 miles. It has been running rough when its caught in low rpms and when you get on the throttle it misses runs rough and will kick the check engine light and then idle/run really rough. It is difficult to get the car comfortably through the low rpms. I had similar symptoms and changed the plugs approximately 4 months ago with the problem nearly resolving... but nows its back and worse because if you get on it it throws the light and runs rough. I was thinking maybe the o2 sensor, mass air flow, fuel filter or fuel pump but thought i would get some other thoughts. Any thoughts. Oh... I do have a cold air intake kit but it ran great with that for over a year so I dont think that is contributing.

Thanks for your help!

[The HACK]

If it's throwing the check engine light, a fault code will be stored in the ECU that will give you some idea as to what is not working.

[bineon]

Hey all! I have a 1999 328i sport with 102000 miles. It has been running rough when its caught in low rpms and when you get on the throttle it misses runs rough and will kick the check engine light and then idle/run really rough. It is difficult to get the car comfortably through the low rpms. I had similar symptoms and changed the plugs approximately 4 months ago with the problem nearly resolving... but nows its back and worse because if you get on it it throws the light and runs rough. I was thinking maybe the o2 sensor, mass air flow, fuel filter or fuel pump but thought i would get some other thoughts. Any thoughts. Oh... I do have a cold air intake kit but it ran great with that for over a year so I dont think that is contributing.

Thanks for your help!

depending on how hard you drive it, make sure it's not a piston compression leak.

[thisismyacct]

my 525 did that a couple years ago and the O2 sensor had gone out so it could be something as easy as that.. hopefully. just run the fault code

[chombo]

I had a similar problem a couple of days ago, ended up being my coils...got them replaced and now, back to normal...

[Robert Venable]

Coils are the most likely cause of the complaint. When you check faults you will see multiple missfire faults, clear the faults, drive and see which return. When you find that a certain cylcinder is missing (#2 for example) simply swap the coil with another cylinder not missing (like #3). Clear codes and if the fault follows the coils replace the coil and boot.

[nuts930]

Definitely get the fault code read and report back. You mention that you replaced the spark plugs recenently. Stupid question, but did you accidently hit any of the spark plugs on something or drop them? If you crack the porcelin around the plug, you will get the symptoms you described. However, if you have the codes read (autozone does it for free), you will have a better idea...