Your problem sounds a lot like the one I fought for a LONG time. It turned out I had two vacuum lines backwards.

When the engine is cold, start it up and go to the EGR valve. Pull on the diaphragm and see if it acts any differently. If it does, you have a vacuum line on wrong somewhere. Mine turned out to be on the back of the intake plenum. If you look at the vacuum hose diagram, you'll see two fittings up there. Once I corrected the vacuum connections, it immediately started running correctly and passed CA smog the first time with flying colors. I promise you that it's the simple things that get you, and you don't want to know how much time/trouble that little vacuum hose cost me.

EDIT: Here is the quote from my thread on the old Black Raider I had.

Quote
Just a quick note to say that I found the reason this damn thing has been giving me fits at cold idle while waiting for the oil to drain. I had the #@%@$%^&#$%^#@% fuel pressure regulator going to the thermo valve instead of the plenum. switched the two vacuum lines, and badda-boom, runs like a CHAMP! ^@^&&#$%@#%#%...

Anyway, I'll be fuel economy increases drastically now, too. Hopefully, I didn't kill the cat or carbon up the system during my bout with stupidity. Off to get a smog check I go. I think I'll let them do a "pre-test" first. I don't need Sacramento to see this thing as a POS with the possibility of a CA buyer...


HTH

Last edited by Oyaji_Jon; 04/05/10 12:43 AM.
73
-Jon
KJ6GVM

As seen on Expedition with TX plates: VEGETARIAN - An old Indian word for poor hunter

Grampa's Trooper
1974 FJ40
1987 FJ60