2008 Cooper S (N14) idle issues
 

My 2008 Mini Cooper S (N14 turbocharged engine) recently had idling problems. Above 1500 rpm it seemed fine, but it would stall -- frequently preceded by a "burp" -- unless I kept my foot on the throttle to hold it above 1500. Even then, it would periodically rev much higher and then come back down to wherever I was holding it.

For the past 2 days -- without my doing anything to the car -- it acts cured. Clearly, the base problem continues to persist but is not affecting the car. That makes me suspect a sensor somewhere. Any thoughts? I want a way to test the potential culprits, identify the offending part, and then replace it.

Thanks.

Were you able to diagnose it? Might have been the VANOS solenoid or ECT sensor?