I remember reading somewhere awhile back about the going up and down of RPM right after starting the engine, but I don't quite remember what to change/swap out. Can someone repoint me to the corrective action for this?

 

Thanks

Could be a number of things, but I would start by looking at the Idle Air Control valve, IAC. If the cold idle is all over the place, then this could be it.

 

Try pulling the codes from the ECU memory.