This is on my 2002 530i (M54 engine) with 111K miles.
On cold engine start up (the colder it is outside, the more likely the symptoms will manifest themselves), I am getting rough idle sometimes. Often times the rough idle goes away once I start driving. Sometimes it doesn't. In those cases when it doesn't, even when accelerating on the highway, I could feel the engine not firing on all cylinders. Sometimes I get the "Service Engine Soon" light . Then I pulled over and switched the engine off. After a few minutes when I turned it back on, the engine ran fine - no misfires anymore. There are some error codes stored.
Based on my google search, specific to BMW world, these are:
P1345 - Misfire Cylinder 2 With Fuel Cut-off
P1346 - Misfire During Start Cylinder 3
Now, this rough idle would sporadically show up ever since the car had about 40k miles after the car sat for days. But it seems like this issue pops up more and more often these days. This morning was actually worse than usual. The car sat unused for 4 days (in unheated garage). I started it this morning, and it ran so rough that it died. I waited a bit and restarted, and kept RPMs higher, and after a while it started running smoothly again.
Spark plugs were replaced at 42k miles. Probably time to replace them again, but the issue was there even before that.
CCV was replaced at 57k miles.
O2 sensors are still original, AFAIK.
Your thoughts as to what could be the most likely culprit? Coils? Fuel injectors? I tried asking on one BMW forum, but did not get a whole lot of good ideas. I might have to take it into the local indy shop after this winter, but if they can't reproduce the issue, they probably won't do much for me.
On cold engine start up (the colder it is outside, the more likely the symptoms will manifest themselves), I am getting rough idle sometimes. Often times the rough idle goes away once I start driving. Sometimes it doesn't. In those cases when it doesn't, even when accelerating on the highway, I could feel the engine not firing on all cylinders. Sometimes I get the "Service Engine Soon" light . Then I pulled over and switched the engine off. After a few minutes when I turned it back on, the engine ran fine - no misfires anymore. There are some error codes stored.
Based on my google search, specific to BMW world, these are:
P1345 - Misfire Cylinder 2 With Fuel Cut-off
P1346 - Misfire During Start Cylinder 3
Now, this rough idle would sporadically show up ever since the car had about 40k miles after the car sat for days. But it seems like this issue pops up more and more often these days. This morning was actually worse than usual. The car sat unused for 4 days (in unheated garage). I started it this morning, and it ran so rough that it died. I waited a bit and restarted, and kept RPMs higher, and after a while it started running smoothly again.
Spark plugs were replaced at 42k miles. Probably time to replace them again, but the issue was there even before that.
CCV was replaced at 57k miles.
O2 sensors are still original, AFAIK.
Your thoughts as to what could be the most likely culprit? Coils? Fuel injectors? I tried asking on one BMW forum, but did not get a whole lot of good ideas. I might have to take it into the local indy shop after this winter, but if they can't reproduce the issue, they probably won't do much for me.