Shitty idle

[Donkey2]

Been putting up with an erratic idle since I put the car together. On a cold start it revs up to about 2K then down to 500 and back and forth, usually stalls unless I hold it steady, or try to. Also, sometimes after taking out of gear on the road it will stick at 2K, have to kill it then restart. I figure the cam may be the culprit. I cleaned out the TB and IAC before and nothing happened. I knew a couple other people with this problem, and no one who knew what to do. Any input is appreciated.

Thanks

[frdfandc]

If cleaning the IAC did nothing for the idle, you will probably are going to have to replace it. Do the following test.


Take a small hammer or wrench and while the car is idleing, smack the IAC. If the idle starts to level out, that is your problem. If not, you are
going to have to start checking for vacuum leaks.

[Donkey2]

Thanks. How much for a new IAC? are there aftermarket manufacturers? or should I go through ford? Is the butane method the best way to check for vacuum leaks?
Thanks again

[frdfandc]

Just get a Motorcraft piece from ford. They probably run around 50 bucks. The aftermarket stuff is junk.


I usually use 2+2 gum cutter to check for vac leaks.