idle problems

A quick rundown.........recently bought a '99 Escort very cheap. The car has had the oil and air filter changed frequently but that's where it ends. Since buying the car I have done a little bit of work on it. Here's a list:

plugs
plug wires
oil change
antifreeze flush and change
serpentine belt
timing belt

Recently it developed a miss and I had the code read at Autozone. Ended up being #4 misfire. I replaced the coil pack first but it ended up being a bad injector. Well, I now have the car pretty much like I want it except for the idle. With the engine warm it idles around 1200 rpm. When I shift form Drive to Park it will rev up to just over 2000 rpm and then slowly creep back down. When Autozone scanned it and found the misfire it also showed P1506 which is an Idle Air Control (overspeed error). I cleaned the IAC valve first (found the info in a post on here) and nothing changed. Next, I swapped another used one on and still no change.

Has anybody experienced this before?? I'm starting to think this may be a ground issue. Thanks for any help.

Has anybody experienced this before?? I'm starting to think this may be a ground issue. Thanks for any help.[/QUOTE]

rough idle could be just about anything. i can only imagine you already tried injector cleaner to help clean out any buildup that may be there. could possibly be a vacume leak somewhere . you say you change the filters regulary....but have you looked at the map sensor which sits just outside the air filter housing. if u can get one at a junkyard somewhere its a real easy fix (about a half hour) but buying it new is pretty expensive. just my 2 cents.

Has anybody experienced this before?? I'm starting to think this may be a ground issue. Thanks for any help.rough idle could be just about anything. i can only imagine you already tried injector cleaner to help clean out any buildup that may be there. could possibly be a vacume leak somewhere . you say you change the filters regulary....but have you looked at the map sensor which sits just outside the air filter housing. if u can get one at a junkyard somewhere its a real easy fix (about a half hour) but buying it new is pretty expensive. just my 2 cents.[/QUOTE]

Try throttlle body cleaner on the butterfly valve. Then check pcv valve then look for a vaccum leak.

the map sensor is on the intake, the MAF sensor is just outside the throttle body. it sounds like avacuum leak to me. you can clean the MAF but i think on the newer ones they dont get as dirty as the older ones. best thing to do is just get a can of carb cleaner, using your head, spray vacuum hoses and such until you hit the leak. ive found some intake gaskets leaking but not regularly but its still something to look for. those arent hard to do at all.

I am going to check for vacuum leaks. Hopefully this will be a simple fix. Thanks for the help.

I cleaned the IAC valve again and soaked it with PB Blaster and let it sit for awhile. Also replaced the pcv valve because it was rather noisy. You could actually hear it rattling through the rubber hose. Popped the IAC valve on and put the pcv valve in and all is well.

The PCV valve is supposed to rattle. I'd say soaking the IAC helped..

The PCV valve is supposed to rattle. I'd say soaking the IAC helped..

I know it's supposed to rattle but this one was unusually loud.