Ok so I used to have this problem a couple years ago and then it went away. When I cold start my truck it will run for about 30 seconds and then the IAC will start to draw in a lot of air. The truck will then idle like it has a performance cam until I turn off the truck and start it back up. Then once I start it up for the second time it runs fine. Wires cap rotor and plugs are all fairly new. Anyone know what could be the culprit? Also I had recently got a code for engine not getting up to temp. I have had a 180 T stat since the spring time and never had a issue, just the other day it threw the code, I don't think it's a weather issue due to the fact it is currently warmer now, then when I had installed it. Any ideas would help thank you.

 

The temp code is real hit or miss, the newer second gens seem to be more sensitive to it. The PCM expects the engine to get up to 195 or so, and when it never does, it occasionally gets annoyed.

Pull the throttle body, rip it all apart, and clean it thoroughly. Reset the pcm, and then let it relearn the idle, see if the problem goes away.