Hanging Idle problems

[Liberto]

Hey guys i developed a hanging of the rpm range. it happens all the time non stop it'll take extra long for the rpms to come back down inbetween gears and even just sitting there reving it. i took the IAC out and cleaned it and its still having the same problem can anyone help me out and figure out what it is???



Joe L

 

[langod]

It just started doing it? Most do it right from the factory.

There's a thread on here (about a year old probably) that describes a mod to fix it. Basically it involves cutting a piece of aluminum sheet to act as a restrictor to the IAC. I did it and I like it.


Edit -- here's the thread with the mod

 

[Kilgore Trout]

Stock TB?

 

[Liberto]

yeah heres the story... i bought my stang from a older man about in his 50's this guy didnt drive the car much at all. Its a 96 GT leather interior car turned 100,000 as i pulled into my driveway all it had done to it was a set of 40 series flows and a K&N drop in replacement filter... the first 2 weeks the car would start up and immediately die if i didnt hold the gas down i figured it was the IAC and so i ordered one at my job and by the time it came in the car was perfectly fine so i guess it just needed to be driven since the guy kept it garaged all winter long... thats when the hanging idle started to happen... if its a normal thing from the factory then ok no big i'll just deal with it when i find that thread but i just wanted to make sure... i dont know much about these 4.6 motors or any of the modular's at all... my dad taught me almost everything someone could know about the conventional V8 fords (my fathers trade is a "5.0 Specialist") so forgive me if i ask alot of "noob" questions about the modilar V8's i'm trying to learn and read up on as much as i can

 

[Kilgore Trout]

It probably just needs a good tune up... Do you have a Haynes manual? At 100k there is a lot of service to be done. One thing I would suggest is SeaFoam. Also, usual stuff like plugs, brake fluid, fuel filter, etc...

 

[Liberto]

It probably just needs a good tune up... Do you have a Haynes manual? At 100k there is a lot of service to be done. One thing I would suggest is SeaFoam. Also, usual stuff like plugs, brake fluid, fuel filter, etc...

i did copper core motorcraft plugs gaped at.54 MSD 8.5mm wires i'm gonna opt for screamin deamon coils because their cheaper that stock and better performance... fuel filter i havent messed with , did a recharge kit witht he K&N i needa find a quality PCV valve so i ight go to dealership cuz the one i have at my work ( advance Auto PArts vineland nj) has like a crappy ass one that needs to be cut to fit or something and i dont wanna **** with that did the oil change today (motorcraft 5w-30 synthetic blend with a Mobile-1 filter) antifreeze was done and i think thats all i did so far

 

[steveb24]

most of its in the tune. a good tuner can get that right out, even better with the aluminum inset mod. all in the "dashpot" setting with the tune, also your idle speed has alot to do with it. the lower its set from what ive noticed, the faster rpms drop under 2k. and ive had my idle set all over the place, so in my case, that stands true.

 

[Liberto]

Like the thread said i got a 1/2 inch brass pipe cap drilled a 3/16 hole in the center and put it in rubber tube directly before the IAC valve itself... made a world of a *****in difference totally worth the fifty cents and 2 minutes. saved me gas, car decelerates alot quicker when in gear, sounds nastier, car is louder when i'm coming down in a gear... just so worth it its rediculous