Hey Guys.

Well, I guess first I'll describe the symptoms.

After the truck has been sitting long enough to cool down completely, it will usually fire right up and run pretty well for 30-40 seconds. After that it idles right down to barely running, but still runs. Usually after driving a few miles and warming up it clears up and runs fairly well. However, usually at stop signs, red lights, etc. it will idle down really low and just barley keep running.

If I'm sitting at a stop light or just idling for a minute or more, the engine starts to surge. RPM's go up and down until I put it neutral or park, give it a little gas till it runs smooth, and then let off the gas. Even then, it only idles well for a short time before it starts to surge again.

Lately it has been stalling at stops. It idles down so low it just quits. Once it does that, I try to crank it over and it wont fire. Whenever it dies like that, the only way to get it started again is to crank it while the pedal is floored.

I bought the truck about a year and 1/2 ago. It has never run really strong and I remember checking the codes right after I bought it. I can't remember what the codes were, but I know there were 2 of them, one related to the EGR system, the other the O2 sensor. However, the truck ran fairly well so I didn't pursue it at the time.

Well, I checked the codes yesterday and this is what I got...

116 - Engine coolant temp sensor
636 - Transmission fluid temp out of range
114 - Air change temp sensor out of range
10 - Cylinder balance test
179 - HEGO
327 - EVP/EPT Below min range
332 - Insufficient EGR flow
334 - EGR Closed
634 - Manual Lever position sensor voltage high or low/or A/C on

Seeing how the O2 sensor is still an issue, I'm assuming I should bite the bullet and get another one of those. Also thinking I should clean out the EGR valve and see if any of those codes clear up. Sound like I'm on the right track?

This was a KOEO test with a cold engine, so I'm assuming for now I can disregard codes 116 and 114. But I don't quite understand what I can do about the 636 or 634 codes. Maybe someone here will have an idea of what those really mean?

Any input would be greatly appreciated. Thanks in advance!