Originally Posted by coachashea
2000 328i will run like its really rough and the check engine light comes on when i turn on the A/C. If I pull over and shut the car off it runs fine as long as i dont turn on the A/C, but it happened last night again and the check engine light stayed on even this morning. The car seems to run fine. Anyone have any ideas.
When you turn your A/C on the compressor put load on the motor, the ECU enriches the AFR to compensate for the extra load in idle. I am thinking it is running too rich, also check your o2 sensor. I am not sure but this is a good place to start. But the best thing for you to do is pay for diagnostic it will also revile other issues you maybe have like vacuum leaks and emission leaks.