SES Light On.... Misfire? [help from the pros please]

[TheKingSim0n]

Okay, So today i started up the X and it was freezing here in NYC, around 26 degrees according to the X. While the car was warming up it started to shake up a lot and then all of a sudden i saw SES light blinking and it stayed on. I connected a OBDII Snap-On E PC and according to the codes I have Multiple Cylinder Misfire, Cylinder 6, 7 and 8 Missfire with 3 different codes.

What could have caused this ? 2001 X5 4.4i with 120K.

Could it be that I need new coils? or maybe I need to check for a vac leak? :/ any help please!

BTW i changed the spark plugs about 2 months ago but i never touched the coils.... any ideas?

Thanks!

[Mikedd]

Might be oil separator hose causing a vacuum leak. Due to the cold I'd start there.

[Tleong]

Originally Posted by Mikedd

Might be oil separator hose causing a vacuum leak. Due to the cold I'd start there.

I agree.... I had the same problem too but it hasn't reoccured. From what I read, it is the oil separator.

[TheKingSim0n]

Ill have a look at that.

Strange thing is that this morning it was 24 degrees and I started up the X and SES light went away and non of the shaking happened.

Still say its a vac leak?

[Mikedd]

Yes, Expansion and contaction with the temperature variations. That separator and hoses will need to be fixed anyway. Consider it maintainence.

[Weasel]

Was probably a missfire... Was the check engine light flashing while the shaking was happening?

[TheKingSim0n]

Originally Posted by Weasel

Was probably a missfire... Was the check engine light flashing while the shaking was happening?

Yes it has been, but I didnt have the time to have it checked out yet, im going tomorrow morning but so far I have been driving for 2 days and SES light went away and it didnt repeat itself again so im hoping its just a vac leak...

[Weasel]

Not a vacuum leak, that would leave the light set steady. The flashing light means there was an active missfire being registered at that time. It takes seeing that missfire a few times before it leaves the light on all the time, just like any fault.

[StanF18]

Hey Simon, Mike, Weasel, TLeong:

I would like to proudly join this "E53 Mis-fire Club" as of yesterday, 4:58 PM, Eastern Time.

Thermometer showed 29F, not what I would call inordinately cold. However my 2006 4.4i begged to differ, and gave me quite the scare when I turned the ignition. Substantial bucking and stuttering of the front end, with a flashing "Service Engine Soon" light. Naively I hoped against hope that this would stop as the X warmed up, but it continued for the next 2 minutes. I put it in Drive and slowly rolled about 100 feet. Problem was not going away! I stopped, put it in "Park" and turned off the engine. I waited a good 30-40 seconds in the gloomy silence. Turned the ignition back on, and everything was back to normal. No bucking. No engine light.

Everything went well today also.

Weasel, assuming this is a 1-time deal, any possibility that engine can be damaged somehow during that 2-minute nightmare? Is this only an E53 thing, or does it happen periodically on other Bimmers? And finally, any action I need to take after the fact, or just pretend like it was a bad one-time deal?

[pochiserna]

Something similar happened to me. I was driving and it was around 32F here in Texas when the SES light came on. Later that day I got the code read and it was P0171 mixture too lean code. The light was on for the rest of that day but was gone by next morning when it warmed up. The SES light came back on again a few days later when the tempature dropped to around 35-36F but again went away when it warmed up later that day. I did not get any of the "shaking" symptoms that some describe and did not notice anything unusual about how the X was behaving but am wondering if there is anything I should check and or replace.

Do i have a vacum leak? Why would the light go away on it's own if there is something wrong? Thoughts?