New Alternator placed in my 2003 R50 manual with 168k by my mechanic. Car will idle when started. When driving the car always stalls. The stalls decrease with the AC on. Was told it was a computer memory issue and the computer will relearn as I drive the car. Hasn't happen. Tried to reset the ECU from this forum and didn't help. Just replaced a new throttle body, Still stalling. My mechanic can't figure it out. Any recommendations? Thanks, badat