I may have gotten off the wagon a bit - I have no vaccuum leaks now but want to preventatively replace some of the associated vaccuum tubing due to age - totally different issue

And the rough "washing machine idle followed by SES light" only has happened 4 times in the past year - apparently its a random Misfire on Cyl 6 with fuel cutoff - which could have its own symptom needing to be fixed, or as was mentioned earlier with jfoj - could be me just pulling the car out of the garage followed by pulling it in and not giving enough idle time to burn off the startup fuel that has primed in the rail, effectively flooding a cylinder.

Will keep you guys posted but the VCG and vaccuum tubing/caps replacement was more of a "well its probably time to take care of these things" - but not necessarily 100% required in the moment.

Besides oil changes and PS fluid reservoir and fluid change, I really haven't done any other maintenance in the past 2 years and she has been running great.

I just went through a similar issue with my X5. The family complained that it was running like it had water in the gas (this has happened a couple of times to us) so I drove it for a week and it was running fine for me. Gave it back to them and the issues came back about a week later and stayed. It threw a bunch of codes (I wrote them down but I can't find them now) which I cleared and then it threw one code for a bad ignition coil on cylinder 1. I swapped it to cylinder 2, reset the CEL and got a new code for the coil on cylinder 2. I put in a new coil and the issue has been gone since.

I was worried that it was a vacuum leak as well but when I opened the oil fill the vacuum was strong. I had to replace the engine on my X5 and when I did it I missed plugging in the EGR vacuum line and I was getting all kinds of codes for lean cylinder 4. If it works sometimes and not others I am leaning towards it been electrical in nature.

My e36 had a fuel pump go bad and the car was running like it had bad gas too. I replaced the fuel pump with a dealer fresh pump only to have that one go bad 2 weeks later. I though it "it couldn't be the new pump" but after million hours of trouble shooting that is exactly what it was. BMW at least gave me a new pump to replace the bad one but I didn't get paid for my wasted time...... Good Luck!

Sounds like normal to me!

All the rubber and plastic parts are exposed to degradation due to exposure of heat/cold cycles and Ozone as most of our parts where not UV balanced so the deterioration is only going to get worse over time. I use Armor All on everything rubber or plastic and just let it sit for 24 Hrs and then wipe off with a micro fiber cloth to remove all the excess. Works perfect so far.

But then I clean and apply it to the CV boots as well so I am Anal and excessive about cleaning. :D All of this compulsion creates one too many auto projects to keep up with also...
I am detailing my M5 for a concourse this spring so I have to stay focused on one vehicle at a time for now. Now I am off to recheck my hand washing of all the brake parts prior to painting.:bustingup

Good luck on the X5 but I think you know what your doing as always. If you pull the plugs you will see which one(s) is fouling. My bet is #4.

Well since I am pretty thorough - I picked up a set of IX Iridium plugs from Pep Girls today (I love if I order online to pick up in store same day they give you 25% off coupon? lol!) for $36, probably will get a fresh set of 6 coils from FCP - again, age related items worry me even if they don't look like they are failing currently.

I will pull #6 before ordering the coils this weekend to see what the plug hole and plug looks like - probably #5 as well to compare them, and be sure I don't have a VCG leak (which will probably get addressed due to age in the next year or 2 anyway)

Also replacing the vac line from lower intake elbow, and the entire hard line/vaccuum line from SAP to back of manifold, along with the associated vac hose back there and the 2 vaccuum caps just to cover my bases.

Will update as I progress - has not happened again since, X is running fine.

Maintenance over the Weekend
 

OK well I swapped out the following over the weekend while doing some of my "spring maintenance" - I still have to change the fuel filter and do an oil change soon but for the most part I think these random misfires were most likely what was mentioned earlier, cold starts that do not let the X run long enough and then on subsequent start, it floods and throws a misfire (which clears itself on restart)

Replaced this weekend:
-NGK "UP" plugs which I put in 3 years ago with Iridium IX plugs
*Note all 6 cylinders were dry as a bone and all 6 plugs as well
-Replaced original Bosch coils with updated OE Delphi coils
Bosch coils looked ok, had some browning on the inner shield underneath the silver part, got a great price on the current coils (OE supplier for the M54 part # is a Delphi coil pack now if you check RealOEM)-Replaced the rubber hose off the lower intake elbow and the vacuum hose with OE braided cloth vacuum hose
Both L connectors were in fine shape - the vacuum hose was especially brittle (part # 11657803732 sold in 1 meter sections from BMW)
-Replaced the SAP line (sold as a complete assembly, diagram below), from the SAP to the back of the manifold
Not the most fun job as its blind and not much space for your hands, but the vacuum line again was very brittle so it was time.
-Also, while behind the manifold there is a check valve in line (#6 in the below diagram), there are 2 sections of vaccuum hose on it, I replaced both of those and replaced the check valve behind the manifold when complete
-Lastly, replaced the vaccuum caps on the back of the manifold
Its done totally blind - per the third diagram there are 3 total caps, 2 small and 1 larger cap, I could only feel 2 of them, and will try to find the 3rd one and replace it, they were pretty brittle as well and if there is a 3rd cap back there, it will bother me if I leave it

If I can find and replace the 3rd vacuum cap, I will have preventatively replaced the causes of vaccuum leaks, which makes me feel better considering the age of rubber hoses/caps and vaccuum system components. All in all a very productive weekend and was glad to see 6 cylinders dry as I do not feel like doing the VCG and Vanos service right now. Thanks to all who chimed in on the thread - going forward I will be cognizant not to pull the car out of the garage and shut it down :D

References:
*Hose Elbow (lower intake elbow) #3 in this Diagram
RealOEM.com - Online BMW Parts Catalog

*Vacuum hose Part #7 in this diagram (also good for replacing the small vacuum hose off the lower intake elbow) and SAP line #3, and vaccuum hose sections #7 off the small check valve (#6) behind the manifold)
RealOEM.com - Online BMW Parts Catalog

*Vaccuum caps (behind intake manifold) #15 and #17 in this diagram
RealOEM.com - Online BMW Parts Catalog

Reference Pic (borrowed from E46F) - Replaced #1 and #2 (caps), and the check valve/vaccuum hose sections are easily seen - replaced both sections of hose on either side of the check valve - the other open port in the picture is the port which the end of the SAP line joins to, so it is used on my car. I think perhaps I only have 2 vacuum caps on the back of the manifold then and got them both?
http://i.imgur.com/GpQiol1.jpg