Guys -
Just finished an oil change on the X5, and was listening to a football game thru the rolled down car windows while doing so. Upon trying to start the car again, realized that I spent a bit too much time changing over the oil (okay, it was a nice day too !), and the car wouldn't crank over. No problem, I threw the car on a battery charger and let it charge away for a couple of hours.
Upon then starting the car and backing down the driveway, the car dies. Started again, was very rough and sputtering - and dies again. Oh great, I'm thinking - what in the heck did I forget/screw up on a simple oil change?
Went to the boards and started searching for cold start issues, etc. Realizing that there was a pretty strong smell of gas to go along with the sputtering symptoms - I narrowed it down to the un-metered air coming into the engine. So the check for this is the DISA unit/ MAF / T-boot - for a simple start. I decided to check the DISA first.
After I pulled it out, I checked that the flap had tension - which it did. It would spring back to open position when pressing it closed, which is the correct action. One thing I did notice when taking out the unit - it slid straight out with no tension at all. Upon examining the gasket material, it was completely flush and flattened down. Based on what others posted, I think changing the gasket out would be a good idea. I removed the remaining gasket material
and then sourced a 55mm x 62mm x 3.5mm O-ring for $1.09. I popped that gasket in, and then started the engine back up - and smooth as silk !!
I also noticed that the "clicking" sound the engine made was gone (alas, another symptom I could have picked up on pointing me the the DISA), and now the engine runs a rock solid idle at 800 RPM.
I know there are plenty of others things this could have been - like the MAF, CSV, Idle control valve, etc. but this might be a good place to start - and the best $1.09 you could spend to solve this issue.