2002 3.0 X5 210,000 miles. I am the first to admit I am horrible about upkeep on my X5. That being said....over the past 9 years of owning my car I have replaced many things. Every window regulator (drivers side twice), all components in the front suspension, alternator, both front axles, coolant reservoir, water pump, coils, valve cover gasket, 5 years ago I actually took it to the dealer and spent $1,100 on something in the throttle area. There are a few other items that I am sure I have forgot over the years. I do all my own work myself. Anyhow...X5 starts and runs fine in the summer. Runs perfect in fact. When it gets cold (not freezing but below 50) it starts perfectly fine but if it sits and idles for more than 20 seconds it will turn rough and stall. I can start it again...it starts fine but if I leave it in park it will idle rough and want to stall again. sometimes it won't stall but when I put it in drive and push on the accelerator it has no power and feels like its running on half its cylinders. I can turn it off and restart it and it purrs like a kitten but starts the process over again. Its as if turning off the engine resets the computer and tells all my coils to go back to work. Once it warms up it runs fine and things are good again. I have done searches and I can't seem to find anyone with the same description as mine. I have found similar problems but nothing exactly like mine. Maybe I am just going into more detail.
Just throwing this at the forum to see if anyone has an answer before I take it somewhere.