My 1999 BMW 3 series, with 112K, full synthetic oil and a 5 speed transmission does great, except for one minor issue. About once a week, when the motor is warm, it dies. Tonight after driving it about 20 minutes on the highway I came to our hill, put it in 1st gear to come up (like always), and then came to the flat part where I put it in neutral to coast the few feet into our driveway. The car responded by idling up to about 1200 RPM, and then dying. It always starts right up the 1st time (even after sitting for 2 weeks), and it is absolutely otherwise reliable. My initial thoughts were something with the idle control valve? Does anyone have an idea? Thanks!
It sounds like an Idle Air Control valve being effected by heat. If the high idle occurs and then the engine stalls all the while the accelerator is released it usually points to a defective IAC valve.