View Full Version : Fricken Idle

12-16-2005, 12:11 AM
Car idles at 1800 warmed up in park with 20 inches of vac. Put the car in drive and the tranny will hold it down to about 1100 with about 12 inches of vac. If you shift the car to neutral while the car is moving the least little bit, the idle jumps to 2400 and stays. (I guess the vehicle speed sensor is doing something for there to be two distinctive idle speeds, 1800 stopped, 2400 rolling.

The car has made a horn sound maybe twice while shutting it off.

The car also doesn't change a bit if you unplug the IAC..........My first guess is i need to bite the bullet and go the the ford house and buy an IAC. Oh, and no codes and no check engine.

Any other ideas.........I'm really dreading chasing vacuhm leaks.

12-16-2005, 12:19 AM
If you unplugged the IAC and it made no difference PLUS you have heard the infamous honking sound as well as have high idle issues then I would say you most DEFINATELY need a new IAC.


12-16-2005, 12:21 AM
the only reason i've been reluctant to believe that's where the problem was, is because when i removed the IAC and left it plugged in I cycled the ignition and the thing moved back and forth, yet I don't know if it was moving in the right directions.

12-16-2005, 01:08 AM
If I understand it correctly, the IAC has a diaphram inside that gets old, dry, brittle... whatever, and cracks or tears and that is what causes the problem.

With your symptoms, I am certain it is the IAC. I am also quite certain that most everyone here will say the same thing.

How bout it guys... anyone else care to jump in and provide a "second oppinion" to put his mind at ease. I know I always prefer to hear more than one person' thoughts on something before layin' out the cash for a part I am not positive will fix a problem.


12-16-2005, 01:35 AM
IAC :cool: Oh, and don't use an aftermarket one if it has a cable lead. Won't fit proper and will cause the idle to race.

12-16-2005, 07:15 PM
one time i unplugged my iac to clean it with gumout , it idled at 1800 for a week till i unhooked the battery for 5 or 10 min then it was fine

12-18-2005, 05:21 PM
IAC sounds like to me. I had the same problem put a new ford part in and fixed it up and it got rid of that cow like honking sound .:D

12-18-2005, 06:26 PM
IAC sounds like to me. I had the same problem put a new ford part in and fixed it up and it got rid of that cow like honking sound .:D

What he said.

Scott Long
12-18-2005, 08:54 PM
IAC. Mine went bad and idled at like 2200 rpm. Couldn't find a vac leak. Made a noise when I shut the car off unless I hit the gas to open the throttle blade and depressurize the intake quickly.

I got one from a ford dealer for around $96.00 and installed it and instantly it was normal idle and no goose honk sound when I turned it off. Mine was 14 years old so I figure I got my use out of it.

12-18-2005, 10:09 PM
I say IAC as well, but I would sooner keep driving the car then waste my money at a stealership. Any parts store will carry the IAC for half Ford's price. AND it'll be a Motorcraft part (packaged by another company). :D

12-19-2005, 05:42 PM
well $71.48 later from my local ford dealer the car idles perfect. About 600 rpm with almost 20 inches of vachum. This poor car has almost 10K miles on it now, it's sad that leaving one sit for that long would cause everything to rot away.

12-19-2005, 05:59 PM
Glad to see your back to a normal rpm .