I just finished the hughes plenum kit and now when the truck idles it kind of coughs and almost dies then does a loud air sucking sound then goes back fine after I tap the gas. I replaced the iac a month ago from a same kind of issue. It drives fine and only does it after cold start. Any ideas?

 

Give it a few days to re-learn the idle. If it still does it, might be a lazy IAC.

Did you clean the throttle body really well?

 

I had just cleaned the tb about a month ago and it seemed to still be clean. Il give it some time to adjust. I did do the reset when I was don't the plenum by holding the button on the dash so I hope it adjusts. Thanks for the advice