The car has about 30,000 miles and from time to time will either die when shifted to reverse,or sometimes will rev up a little then shift a little hard into rev. There are no codes set and it just does it now & then,always after the car is warmed up and has been driven forward for awhile. Any ideas Thanks Dennis
GM issued a PCM program update to address that issue. Contact a dealer with your VIN to see if it applies to your car. If it does, have the dealer re-flash the PCM.
If it does not apply, the thread suggests you start by checking for vacuum leaks, clean and reconnect battery cables and grounds, then remove the ICM connector and do the same while tightening up on the connector sockets. Finally do the same for the intake sensors. Remove the IAC and clean it.