Yes, the check engine light went on and gave me three codes.
Yes, I tried adjusting the idle speed screw and nothing changed. I removed it completely and noticed the "O" ring had become hard plastic and allowed some play when installed. I replaced the rubber "O" ring and re-inserted the screw, it now has a snug fit. I have not restarted the engine yet.
I worked on the EGR valve, re-started the engine and it ran alot smoother. The idle adjust screw now responds when it is turned in either direction. Timing is now steady at 5 deg. and RPM is set at 750. Took it for a test drive and it runs better.
It still has a slight studder when idling at a stop signal, & lacks power.
Yes, your reply was helpful.
I appreciate your advice.