I have a 92 5.7 TPI that runs perfectly until it reaches operating temperature. Then it surges at idle (especially in gear) and the motor runs roughly. I had a trouble code that indicated a problem with the EGR system. I replaced the EGR valve, but the problem persists. Any advice?

THanks,

Ken

 

Disconnect vac to the egr so it will not open and see if it still does it. If that fixes it then replace the egr sol valve.