Originally posted by 5point1:
Here's what would happen:

You start the car, it revs up to almost 3000 RPMs, then, if it doesn't stall right away, it will just keep going way down to ALMOST stalling, and then SHOOT right back up to 3000 RPMs, and then go back down and ALMOST stall, and then SHOOT back up etc...etc...it would keep doing this like 10 or more times while idling until eventually it would just completely stall out.



This is a whole different ballgame. This does not sound like a DPFE or EGR problem at all. I'm thinking the Idle Air Control valve needs a good cleaning.

If I was the guy spending the money, I'd do the TB cleaning, and start the car up to see if that helped. The channels behind the TB gasket are probably so caked full of carbon that you can't even see them.

If that doesn't help, its a simple task to remove the IAC valve to clean & lube it. THAT should get your idle smoothed out real nice. Maybe you can get a CEGer to visit you & let you install their working IAC valve. That way you know if it will solve the problem before you spend money on one - if needed.

Both these things can be done in one afternoon by a novice mechanic in the cold northern air (although I'd let the IAC valve dry off indoors before re-installing it).

Must be that jumbly-wumbly thing happening again.