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.
I had none of the typical symptoms of a blown head gasket either... the oil was clean, no steam, started and ran nicely (except to the first 5 min of a cold start, which I'm still trying to diagnose). I DID have a loss of coolant, and the symptoms were very much as you describe on your rig. When I removed the head I was AMAZED that the truck ran as well as it did... and I also passed emission testing here in NJ with flying colors... in fact, TOO GOOD! The guy tested it twice cuz he thought something was wrong with the results. I now am thinking that maybe the glycol that was evaporated in the exhaust stream may have been playing games with his machine.
The temp sensor is VERY easy to check! Get an el cheapo ohmmeter and pull the connector on the fender well and test the thing! How far are you from Tinton Falls ? You are welcome to come down here and use my ohmmeter if you don't wanna buy one.
I think yer runnin' around in circles with your diagnosis... do a compression check also... I was gonna suggest a head gasket problem myself, but didn't wanna be the bearer of bad news, but the more I think about it, the more I believe that may be the case... possibly in ADDITION to other troubles with your throttle body.
Good Luck!
Jeff
