high idle PLEASE HELP ASAP

When I start the car the idles go real high (upto 5000+) and stays there, it drops a little but stays pretty high. I tried pull a sensor on this airbox looking thingy and the idle went even higher and then back down when i put it back in, but still idles real high. Whats the usual problems that cause high idle?

What year what motor?

When I start the car the idles go real high (upto 5000+) and stays there, it drops a little but stays pretty high. I tried pull a sensor on this airbox looking thingy and the idle went even higher and then back down when i put it back in, but still idles real high. Whats the usual problems that cause high idle?

I too have this problem, on my 1997 T-Bird V6 3.8L engine. It has been happening ever since I first got the car, only now as it is getting older it is starting to become more frequent. It is a totaly random thing, it does it when it wants to. The car has 122,000 miles and has been regularly maintained.

I noticed it when I first start the car in park, the tach needle quickly shoots up to about 2,000-3,000 rpm. Then when you put it in gear it drops to 1,000-1,300 RPM but not without a violent jerk and a rough idle when I get in gear. Once it is in drive, I have to put more effort into the brake pedal becuase it wants to lurch foward and run on its own. There is no check engine light when it does this.

I have tried using different octane levels and brands of gas, replaced my MAF, replaced my spark plugs, replaced my O2 sensors and nothing seems to work.

If anyone could help it would be greatly appreciated because it is starting to become a serious safety issue.

Hot knowing much about the car, it sounds like a throttle positioning sensor problem and/or vacuum leak.

Hot knowing much about the car, it sounds like a throttle positioning sensor problem and/or vacuum leak.

I have checked for vacum leaks and none were found. I havent checked the throttle positioning sensor yet, but I will give it a stab if possible.

Hey,

Our '88 Bird had accelerating/ high idle problems--hard to brake, etc.. (V-6 3.8). Ford dealer could not help. Took it to a local specialty shop known for electrical systems. They cleaned the injectors and told us that injectors get partially fouled and then the computer over compensates---and you get this problem. Problem solved by having the injectors cleaned at the rail. You can buy a kit for about $40 if you are savvy enough to do this work. It cost me much more at the shop. They used a cleaner I think called 44K --I still have the can. Did our other '89 Ford as well. This was over 5 years ago--no problem since.

One problem I had on a '90 Grand Marquis with a 5.0 was the PCV valve came out of the back of the engine (not in the valve cover on my car, was in the middle of the back of the motor). It took me a day or two to find the problem. Once it was back in, it idled normally. The only difference is mine was probably only running about 2000-2500 RPM, not 5000.

Rick

This is a common problem with our cars. It sounds like the Idle Air Control Solenoid. To check it, Remove the wiring and turn the IAC 1/2 of a turn and replace it. (Note that the wiring CAN NOT be plugged back in when it is installed this way).

Then start the car. It should reset the idle and you can then limp the car around until you can get it replaced.

where is the IAC located? pics would be appreciated , thank you

where is the IAC located? pics would be appreciated , thank you
It's mounted to the top of the Throttle Body with two 10mm bolts. (On an SC it's on the side). I'll see if I can find a photo, but you cant miss it. It has a small plastic connector (2 or 3 wires) pluged into it.