That is not how our IAC works. Our IAC stays open at all times to prevent stalling during sudden TB closeure. If it is stuck closed it can cause stalling and stuttering. A IAC can be cleaned. The only time the IAC is supposed to be closed is during cold start up idle.

 

Ok guys so now i've replaced the IAC still nothing... I've also been told by the guy at our advanced in the area to replace the thermostat sense it only does it when its first cranked on... At this point i didnt care, so i tried it and it doesnt resolve the problem, and i still have no engine codes, soo any other Ideas?

 

as soon as i saw what spark plugs you were running, that was my first thought of where you problem is coming from. i kept reading and it seems others are thinking the same thing.

mustangs do best with stocker type plugs, and not all the triple bling bling sheeeeit.

seriously...im thinking plugs may have somthing to do with it.

just curious...but...when was the last time you changed out your fuel filteR?

 

Well i've never changed my fuel filter, and it was doing this before i put those spark plugs in. I hoped that they would fix the problem originally but they didnt.

 

were they stock plugs that you replaced with the current ones? or were they also triple platinum (already in there)? if they were the wrong kind in there from the go, and then you replaced them with more of the wrong kind...then of course....it wouldnt fix anything. just a thought.

not sure if the fuel filter would fix your problem or not....but i CAN tell you, that if you have never changed the fuel filter, then it may be time! you would be suprised at how it can fix the sluggishness feeling and gas milage. they are only $11 at auto stores! it may not be 100% necassary but i change my fuel filter out, every other oil change!

 

well, i think you should do a complete minor tune-up, spark plugs, wires, FUEL FILTER, pcv valve, ya know just the basics, then go from there.

 

oh yeah, and im pretty sure if the maf was screwed up it would set a CODE.

 

Could an air leak somewhere cause this?

 

Yes. A vac leak could be causing this. What code are you getting?1151? 1131?