JJ'89

Can someone explain the fast idle provision? Mine's an '89 pickup with 160,000 miles. Runs great otherwise, but it has always had what seems to me as an grossly excessive fast idle speed. Even in a Fresno summer it just idles too fast when a cold start. I'm familiar with Rochester and Carter 4-barrels, but for fuel injection I'm lost. Is it covered in a factory manual or Haynes? Thanks, Jim

Dr Phat

Look into IACV or "Idle Air Control Valve". On the 22RE there is a valve that opens and closes based on coolant temp flowing through the throttle body which opens a path around the "closed" throttle body at idle. Once it heats up the valve closes and blocks the flow of air around the throttle body. The valves can stick with age or obviously fail completely. They still sell replacement valves for the 89+ years if you cannot fix yours. There plenty of info on here and Google, just need to know what your searching for. Obviously check for vacuum leaks as well! Hope this helps.

2ToyGuy

Also, you might want to take a look at the o-ring on the idle adjust screw. If the o-ring is cracked, broken, whatever, it might be allowing way too much air in.
Easy to check: Remember, the idle adjust screw is under the screw that is covering the whole affair. Turn the idle adjust screw in until it stops. Not super tight, just until it bottoms out. Count the turns it takes, including 1/2 turns, 1/4 turns, whatever. Then unscrew it all the way out. Remove the idle adjust screw completely. The o-ring is near the bottom of the screw. If you've never replaced it before, chances are it's a 30+ year old o-ring. Probable needs replacement by now.
The o-ring is available at most auto parts stores. A lot of them sell o-ring sets, that almost invariably include rings that will fit this application.
I've noticed that a thin layer of Vaseline rubbed onto the o-ring before installation will make it seal better, and last for much longer. Works for any o-ring you might replace.
Anywho, put the screw, with it's new o-ring on it, back in. Screw it all the way in again, and back it out to where it was when you started this whole affair. That's a good starting point. Then hook up your tach, and once the truck is good n warm, set the idle to 850. Might be a good time to double check the timing according to the FSM. Once it's correct, double check the idle is still at 850.
Note: Don't use the tach in the truck's instrument panel, if any. There's no way to be sure it's anywhere near correct to the real world. Always use an external tach. Or, if you can still find one, a tach/dwell meter I still have mine, and it still works great.

As mentioned before, though, It's probably the IACV opening too far.

Good luck to you!
Pat☺

Co_94_PU

iTrader: (-1)

Your cold idle rpm isn't relevant so long as the RPM is inspect once it's warmed up..

1600-1800 cold isn't abnormal.

Co_94_PU

iTrader: (-1)

The iacv or aav (aux air valve) isn't known to me to open to far..

The OP didn't give us any quantifiable data IE no rpm numbers, leaves us to just guess and hypothesis.

JJ'89

Thanks for the help guys. I see there are tons of utube videos, and I actually have the factory manual that I scrounged off ebay back in '04 when I bought the vehicle. In my old age, I've lost enthusiasm for DIY auto mechanics. I guess I'll have to drag out a dwell/tach and multimeter and get after it. I know I have at least two of them somewhere, probably more.