Hi, our Grand Cherokee will frequently die when it's cold. It is always when switching from reverse to drive after backing out of the garage, then doesn't do it again, though it will occasionally idle rough and at varying RPM while at stop lights. Wondering if someone could tell me which sensor would cause this. Does not give any code/check engine light. Thanks!

 

Probably Idle Air Control (IAC). Try cleaning it.

 

Thanks, I tried that before with no difference noted. Might try it again though. Any other ideas?