RiCe_KiLlEr

I went with a blow-thru maf when I installed my supercharger and I place my iac hose after the maf 6-12 inches from the TB. My problem is with the iac valve plugged in she idles high and the RPMs hang while driving. She stays at aroumd 2k RPMs and will not come down until I am completely stopped for a few seconds and when it does idle down it idles around 1500rpms. Now when I unplug the iac valve she idles around 900-1000 and the RPMs don't hang at all and when I drive or rev it the idle won't hang.

One day I got bored and hooked up my old CAI and hooked up the stock maf and all the hoses like it should be n/a and with the iac plugged in it ran normal. The car ran rough with the iac unplugged.

The car has been tuned with the blow-thru maf. Did my tuner not do something wrong or is their something else wrong? My tuner couldn't figure it out and he went over everything and said he couldn't find any vacuum leaks that could potentially cause it. Thanks for the help

RiCe_KiLlEr

Did my tuner not do something right**

Z28KLR

Car should not run AT ALL with the IAC unplugged.

That's all I can definitively tell ya though. As far as why it ran different when you swapped out induction piping I'm at a loss.

As far as replacement IAC's, so far as I've ever heard people generally have mixed results with parts store replacements, and so with that it's generally recommended to stick with a Motorcraft part for this.

RiCe_KiLlEr

Already replaced TB sensor and IAC valve

school boy

Your throttle body needs adjustment. Unplug the iac and turn the screw on the tb stop until you get the rpm you want. Then plug the iac back up. The iac's job is to let air past the tb when needed. This may not fix your hanging rpms but as long as your iac is working properly, your idle should be much better.

Bman2000

interesting that i had a similar problem. My tuner ended up playing with something, like the reaction rate of the iac or something its been a year almost so i cant fricken remember. I tell ya it sure is annoying though. I had it mostly fixed to where its didnt hang too bad. my idle never was that high though it stayed around 8-900