this is exactly what happened when replacing my plenum gaskets I changed the iac and it still did this until i left battery unplugged for 5 min so I would start there

 

not paying mechanic anything yet. he is friend and neighbor and stops by on way home from work and does couple of things for us.
So Dr. Donut, you are saying to unplug battery, what does this do?

 

I meant after you replace the iac because I believe it resets the computer for the new switch but i would change iac then unplug bat for a while this is how i fixed mine which had the same symptoms as yours including the popping hope this helps

 

if you don't reset the pcm then it will eventually learn that there is a good iac there. i believe it can take up to 200 miles.

 

i have the same problem... just when i start it up. 5-6mins later shes just fine!! i just bought a new IAC(today). next will be the upstream o2 sensor since mine has 111k on her..

 

thanks for info everybody, told son to unplug battery but he hasn't done it yet. also mechanic put on computer and says that iac is staying opening or something. something is not telling it to close properly and he is checking into it. but i will still keep in mind what everybody is saying. keep you updated. thanks again

 

just wanted to update everyone. I believe we finally got the problem fixed!! The mechanic said the problem was terminal and wires to 02 sensor, fixed wires and put on new sensor, truck hasn't done what it was doing since. Thank God!!!
I want to thank everyone for the help and suggestions, you guys are the greatest!!! Be assured any more problems and i will be back, again thank you all so much for your help