1996 Ford Explorer. 4.0 EFI
Question: The engine stays at idle high, goes higher once I accelerate. The truck sat in my garage for two years because the transmission when out. I just recently got the transmission fix.
Answer: there are a couple of things that could cause this problem on your Ford. Since the truck sat for such a long period of time, you may have carbon buildup inside the throttle body. Or a buildup of residue causing the throttle plate to stick partially open. There is also an idle air control valve that does exactly what it says – controls idle. It may be sticking or not functioning at all. If the check engine light is on get a scan of the computer codes. There may be a code set for the throttle position sensor. Also known as the TPS. That sensor could cause your engine speed problems as well.
There is a coating inside the throttle on Ford cars and trucks, and it is stated that you should not clean them with any cleaner. But I have done it with a small amount of cleaner without any harm. Also check that the throttle cable is not binding. You can disconnect it and see if it moves in out freely. Be careful not to break it if you disconnect it, anytime cars and trucks sit for a long time things under the hood become brittle.
Comment: I have seen this problem on the ford Explorer before. Either the throttle cable is all rusted up inside and is just sticking and staying when you press on the gas pedal more and more, or the actual gas pedal is sticking. Anytime a car sits for a long period of time, things start to bind up.
Remove the throttle cable from the engine and from the gas pedal. Move the cable in and out by hand to see if it moves freely. If not, either replace it or spray some WD-40 in it and work it until it frees up.
If it is not the cable, move the throttle blade and gas pedal to see which one is binding up.