"You got to have a plan, man."

Yeah, but the plan isn't working. This all started back in the Spring readying the beast for inspection. It's had a low idle for a while but I figured a tune-up was in order and having read the number of posts with intake gasket problems I figured I'd change the intake side gaskets while I was at it (200,000 miles had passed since it was last done). Did it all by the book (Haynes) adjusted valves, changed out plugs, cleaned everything ('cept for that EGR passage I didn't know existed) set the TPS while I had the throttle body off (using your very good instructions from a previous post, Michael), put it all back together and... low idle. I blew enough carb cleaner through the air bleed passage to confirm there's nothing blocking it. I just can't get the RPM's
past the 450 mark even with the screw backed all the way out. Without the RPM's at the right level I can't set the timing correctly so I approximate. I think what I'll do is removed each vacuum tube that hooks into the common chamber and plug it to see if the engine speed changes. I replaced all the rubber tubing two years ago, but I've always been suspicious of all those little pneumatic switches mounted on the fender walls.

Oh, and I passed emissions; very low hydrocarbons (72), average CO
and just under the wire on NOx. I'm pretty sure the NOx issue was a function of the plugged EGR. I've got no indications of a head gasket problem (no milkshake in the oil pan, no brown globules floating in the radiator, no steam out the tail pipe), mileage is excellent; If I could just get past this low idle and slight stumble on accleration I'd be happy. I'll agree the aux air seems bullet proof. By-passing it on start up changed nothing. Plugging it when warmed up also changed nothing so the pointer goes back to the temp sensor.

And the drive in this morning the temp guage stayed at the 1/4 mark...might have had something to do with the fact it was 70 degrees outside instead of 90 degrees... Thank you for confirming that thermal air valve "open" means "Too Hot". It didn't seem right adjusting the engine speed with all this air bypassing the throttle plates.