I recently purchased a super clean 2008 Mini Cooper base. It starts and runs great until its warm then it will idle at 1500 when stopped at traffic. It will drop to 850 after clutch is pressed and the car is still rolling, but rise up after stopped. When driving it dosnt have an issue with high rpms(won't try to run away), but does have some hesitation at lower rpm and higher rpm.



Previous owners put in a new oem MAF due to code but didn't remedy problem. No codes, after its warm it can be difficult to start without giving it a little gas. If i turn on the AC it will drop to a normal idle and stay. Any ideas? it has 106000km. Thank you,

 

I would start by checking for a vacuum leak, the vacuum hose to the intake manifold is a prime candidate for cracks and leaks not visble under the plastic sheaf. You may even hear a vacuum leak.

 

I did check for leaks with no luck, i ended up taking it to a shop they checked with a smoke machine and spend a couple hours diagnosing. It ended up needing a software update from Mini! BAM! runs perfect, cost was an hour at shop and a $350 file from mini. thank you just wanted to put this out there because I have never heard of this before.

it did throw to codes while diagnosing as well P115D
and P0171.