Random M54 Misfire on Random Cold Start checklist...PROBABLY SOLVED
 

UPDATE: CODES POSTED 3/29/16 on Page 3!!!

UPDATE #2: Maintenance performed on 4/18/16 - Marking Thread title to "probably solved" as it looks like probably the times it has happened have been most likely my own error -

Thought I'd throw up a thread for this although I have yet to scan the X with DIS (will do so in the next day or two)

- Second time in a year that upon first cold start in the morning leaving for work, while I normally wait for the high idle to die down a bit before I start driving, I start to feel a bit of vibration in the car, then some sputtering under the hood giving a misfire, then SES light is on, car runs like crap
- Last time it happened I drove 5 mins down the road to Panera to get coffee, turned off the X, came back out, started up and 100% fine, no SES and running perfectly
- This time I went to the end of my driveway, turned it off, and restarted the X, running perfectly fine from there on out
-Last time I scanned it looked like a few misfire codes, nothing else crazy, but I just cleared them and ignored it to see if it happened again (10 months ago)

There is currently 82k miles on the X, it had about 1/4 tank in it today, always at Shell (93) stations but I only fill up once every 3 weeks or so, maintenance items completed to date since I've taken ownership:
-Plugs replaced with NGK's 2 years ago
-DISA rebuild kit from GAS with new seal
-Cleaned throttle body last year after CCV job while it was out
-Lower intake elbow
-Have an AFE intake with Dry filter and that was last cleaned last year

I run Techron through the tank every 6 months or so, along with Lucas UCL when I can. I have a Mahle fuel filter on my workbench waiting to go in, and an oil change to do. Battery is a 3.8 year old Bosch 900 CCA from Pep Boys that the PO put in before he sold the X, no charging issues.

Any thoughts? I may take to my local indy who has Autologic to diagnose, with the cold weather coming I may have them perform my winter maintenance and solve this issue so I'm not worrying about it.

Is it a random misfire or cylinder specific? Coils can give up the ghost at this age/mileage sometimes.

On first blush, sounds like a vacuum leak to me, RB. I had the same problem once and found I had a very small crack in my intake boot, as well as a cracked line from the SAP to the intake manifold. I'm sure lots of others can share their experience as well.

id say coils but this was the start of my problems when my fuel pump went..

Check this thread over on E46fanatics: Cold weather misfires and CEL, common issues $50 fix! - E46Fanatics

Will let you know what the scan with DIS points out, I'm not discounting it might be a random coilpack.

Thanks for the link to E46F, I will check it out. Wouldn't a vaccuum leak happen more often however with the misfire? I changed that lower intake elbow so thats not it, but i'm not discounting a vaccuum leak.

And probably worst case scenario I'm thinking fuel pump but I'd think that would happen more often as well.

I had similar issue a few months after replacing the intake elbow and it turned out to be some of the related vacuum hoses and a cracked vacuum fitting. As the engine transitioned off cold start, it would stumble. Once fully warmed up, it ran better, but still with a bit of a rough idle. I agree with crystalworks on the coils too. My two replacements came at 124,000 miles on the e53, but my wife's e46 had three go bad at 100,000 miles.

2002 X5 3.0 290,000 miles
2004 325i 123,000 miles

^When I last had the intake elbow those 2 hoses and the fitting looked ok on reinstall, I'll give those a look, Gary what was your cracked vaccuum hose from the SAP to the manifold so I can look at that too?

^ In a conference call with the Fatherland ATM, but I'll get you the details ASAP.

The line I replaced is #3 and #4 in the drawing. You'll most likely need to remove the Cabin Air Filter Housing to get to the hose connection on the back of the intake manifold.