I am having the same issue with mine no backfire or stalling yet its starting to drive me nuts as well. Pretty much changed or checked evrything. I will be changing coolant temp sensor to see if that helps as is tied to idle control. If you have any Ideas i'm game to try them. By the way does anyone know what the vacuum specs for these trucks should be

 

i dont know what the vacuum specs are for it. but wouldnt the coolant temp sensor throw a code or atleast be in the computer as something its monitering? Does yours idle low or high? Cuz mine dosnt idle high or low its just rough. besides when it drops occasionally. and im pretty sure mine is the iac valve becasue if i block the hole in the tb with my finger it idles way smoother.

 

What hole? Sounds like you are missing a vacuum line.

Is it hard to steer this thing?

 

He's talking about the hole on the top back of the TB that feeds the air to the IAC sensor.

 

Did you clean the throttle body out also I know when I replaced my IAC it had a rubber O ring that sealed it from air leaks is the O ring missing?

My TPS had an O ring also but the new one didnt come with one.

If you took apart the throttle body to clean it you could of tightened the screws down to tight and warped the throttle body putting it back together causing air leaks those screws are just snugged down never cranked down. You probably know this but I included this as info for those that dont.

 

Yes he was correct i was talking about the hole the iac seals off. I do still have the o-ring in place and i didnt crank them very tight. I also did clean the whole tb and put a new gasket on while i was there. I fixed my idle to almost perfect with a good iac and re-routing the coil wire as the tsb says to do. I also changed the plugs because i had one heck of a fould plug on cyl 3 because of the misfire for so long. I still have what sounds like horrible topend noise but at idle my valves are the quietest of any motor ive ever owned(owned alot of dsm's lol) but anyways for now the cel is off and holding we will see if it stays away or not. I got a new brake indicator light on my dash to deal with now! YAY!!!!

 

So you had a bad IAC and a fouled plug.

I need to replace my IAC the one I have its a used one I swaped from another TB, plugging in a new downstream O2 this friday now all I need is a new MAP and I have replace all my sensors with new ones.

 

Im on my way there to lol