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Discussion Starter · #1 ·
This thread is my attempt to document my current and future diagnosis of a random misfire. Hopefully, this will make someone's life a little easier.

On Sat, I returned from travel after five days, getting stuck an extra 2 days due to the recent snowstorm. Luckily, the airport did not get pounded so getting my car out was no problem. It was cold but not that cold (~30F). However, as soon as I started the car, I could tell something was not right. Seeing the Check Engine Light confirmed it. It sounded like I was missing a cylinder. Not good but it did not sound too bad and the car was drivable. The primary symptom was a lack of power. The misfire continued for about 10 miles. The car would sound worse when the revs went above 2K so I kept the speed down around 55. Somehow, at the 10 mile mark, the CEL disappeared and the car suddenly regained the missing cylinders and everything was fine for the balance of the drive. This is apparently contrary to what is supposed to happen (fuel shutoff should remain off for this engine cycle). When I returned to my house, I pulled out my Peake code reader which identified cylinder 1 and 3 as misfiring. No other codes were present. I cleared the codes and left the car. Yesterday, I started the car and the engine fired right up on all cylinders. So, at this point, I have no clue as to why this happened. My car is well maintained, has been trouble free and normally garaged. The multiple day outdoor parking is the only obvious anomaly to normal routine.

I will use this thread as my guideline (Thanx, BB!) for diagnosing this problem as I go forward. http://www.bimmerfest.com/forums/showthread.php?t=500419&highlight=misfire At this point, since it is still winter, I will likely see if the problem recurs before I start tearing things apart.
 

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Discussion Starter · #5 ·
So I start my car to go pick up my brother at the airport and lo and behold... I am stuck fast on a patch of ice in my outside parking spot. My car has been sitting outside while my brother's e46 occupies my garage spot. So I take the Highlander to pick him up. At least the car started right up without any misfire or CEL. Anyway, I finally dig my wheels out (yes, we got more snow Sat nite) and the car fires up again with no issues. More snow is coming tomm'w. Then it finally warms up. I will begin the serious troubleshooting once the temps warm up above freezing.

I doubt the plugs are loose and will check them for fouling this weekend. If it were loose, I'd have blown it out by now. FGortunately, I have a Time-Sert! :thumb up: And I doubt it's a coil issue as I had two cylinders misfiring. Multiple simultaneous coil failures seems unlikely. We shall see...
 

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my 328is does this when its really cold.. but normaly sorts it self out a few min after running..

It runs with a miss when cold after a few days of not running at all..


you have a mis that is temp related..
ICV, or air leak

the 6's seem to do this a lot more then others.. IDk why

if it makes you feel any better I can tell you, that your chaseing a ghost..
 

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Discussion Starter · #7 ·
if it makes you feel any better I can tell you, that your chaseing a ghost..
:lmao: Time to call Ghostbusters! :rofl:

Actually, it does make me feel better. I suspect this is an isolated incident but will continue to monitor and post updates. The car fired right up and ran great when I finally put her back in the barn. We shall see...
 

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before you go chasing it like i said... wait for it to become more pronounced, when it becomes a regular thing.. then worry..

mines been doing it for what 5 years now??
 

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Fudman, a friend of mine had multiple misfires on his e46 with M54 B30 engine.
Here is what we did (and so far so good):

Changed the DISA O-ring (had vacuum leaks around that bad OEM O-ring design). Pulled out the ICV - was clogged - and cleaned it. Cleaned the TB. Buttoned up, erased the codes. Started the car, no dice. Started nice, but after a few minutes it started to misfire again. Head scratching time. Went back, erased the codes AND checked old codes - bingo!!!!! There were some old non- related codes. Erased these codes, and the new misfire codes - car run like a champ. Then after a few test drives around the block, we reset ALL adaption values. Car runs like new.

GL
 

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same exact issue on my 02 540 M Sport. If it's really cold and I don't drive the car for a few days....stumbling, rough idle. CEL comes on. After she warms up, all is good and the CEL goes away. Will be fine is temps are above freezing or if I drive it everyday. Dealing with a coolant leak, bad ignition lock, and having an oil change done at an Indy this week. I will tackle this once it gets warmer and I can DIY it myself.

Please post back if you resolve the issue. I will do the same.
 

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same exact issue on my 02 540 M Sport. If it's really cold and I don't drive the car for a few days....stumbling, rough idle. CEL comes on. After she warms up, all is good and the CEL goes away. Will be fine is temps are above freezing or if I drive it everyday. Dealing with a coolant leak, bad ignition lock, and having an oil change done at an Indy this week. I will tackle this once it gets warmer and I can DIY it myself.

Please post back if you resolve the issue. I will do the same.
Some rubbers shrink (and metal components) and let false air pass by (vacuum leak). Once the rubber (and metal) warm up they seal up and all is good. I would change all the old rubber seals that show air going by - smoke test with cold engine. :thumbup:
 

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Discussion Starter · #13 ·
Fudman, a friend of mine had multiple misfires on his e46 with M54 B30 engine.
Here is what we did (and so far so good):

Changed the DISA O-ring (had vacuum leaks around that bad OEM O-ring design). Pulled out the ICV - was clogged - and cleaned it. Cleaned the TB. Buttoned up, erased the codes. Started the car, no dice. Started nice, but after a few minutes it started to misfire again. Head scratching time. Went back, erased the codes AND checked old codes - bingo!!!!! There were some old non- related codes. Erased these codes, and the new misfire codes - car run like a champ. Then after a few test drives around the block, we reset ALL adaption values. Car runs like new.

GL
Doru,
It's probably not my DISA as that is only about 18 mos old. Could be the ICV. I don't have INPA, just the Peake. I erased the old codes and the car has been fine since. It may just be one of those spurious problems that comes and goes. We shall see... Can't drive today, though. Another 6"-8" falling. There's no room to put it!
 

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First time I cleaned the ICV was when I hit +/- 90 K miles. the ICV didn't even budge (it's supposed to move freely). It was all kind of carbon deposits crud. But this was in the summer time when it was hot, so really no "cold" start per se. In cold weather this is more pronounced, and it might give you codes. The valve will be in a stuck position: open, closed or in-between. Pending where it sits, it can give you the code right when you start up the car.
 

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Discussion Starter · #15 ·
An update: So it's been a month now and the misfire issue has not recurred. No new or other symptoms whatsoever. I have taken no actions other than clearing the codes. I only drive a few times a week now so the car sits for a few days between drives. I've driven a few hundred miles, done multiple trips to the airport and it has sat outside for multiple days in cold weather but there has been no sign of this misfire. I even had the car inspected so there is no code stored on the computer. :dunno: I guess I can chalk this one up to the electrical gremlins. This update is of no use to anyone other than sometimes problems cure themselves and I hope it never happens again :thumbup:.
 

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An update: So it's been a month now and the misfire issue has not recurred. No new or other symptoms whatsoever. I have taken no actions other than clearing the codes. I only drive a few times a week now so the car sits for a few days between drives. I've driven a few hundred miles, done multiple trips to the airport and it has sat outside for multiple days in cold weather but there has been no sign of this misfire. I even had the car inspected so there is no code stored on the computer. :dunno: I guess I can chalk this one up to the electrical gremlins. This update is of no use to anyone other than sometimes problems cure themselves and I hope it never happens again :thumbup:.
Oh thanks god another car heals itself, Sweet...:beerchug:
 
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