I just changed my antifreeze, top and bottom radiator hoses, the 2 hoses coming off the thermostat housing, and my thermostat (it had a 180 degree and I replaced it with a 195 degree). I shot some aerosol cleaner into the throttle body and WD-40'd the throttle cables.

Now, I have a fast idle that doesn't drop down. What should I check for?

Gary

 

Unplug the IAC with the engine idling. If the idle does NOT drop, it's probably stuck. Replace it.



If it DOES drop, plug it back in & see if it jumps right back up. If not, it's probably stuck. Replace it. If it does, get a Haynes manual & a multimeter, and test the TPS, ECT, & ACT.

. . .

 

How do I recognize the "IAC?"

This is the first Ford I have ever owned

 

Also, click my signature link & look thru the General Purpose Pics album - it has a few shots near the top with everything labelled.

 

Okay, checked the voltage and the ohms on my IAC. They both check out. When I unplug it, nothing changes. I removed the silver cylinder and pushed the little plunger with my finger and the idle speed really increased more. I then removed the entire valve and shot some carb cleaner in the two holes and moved the plunger back and forth. Where to go from here. I am gonna remove my negative battery cable and touch it to my postive to erase the KAM.

 

Do not touch the battery cables. And resetting the KAM won't change anything, anyway.

With the IAC unplugged, the engine should BARELY keep running for a few seconds, and then stall. If it doesn't, you have a vacuum leak somewhere. That leak COULD be at the throttle plates (because someone messed with the throttle stop screw), or it could be inside the brake booster, or at the plenum-to-manifold gasket, or any of several other places. Use a 3' piece of garden hose as a stethoscope with the engine idling to find the hissing.