95 bronco problem

hey the motor a 5.0 fuel inj motor runs great but the idel is not right sometimes it idels ok other times when you put it into drive the idel goes up and down it is driving me nuts then it idels ok again what do i need to fix or do love my truck just painted it giants blue thanks in advance:rolleyes::rofl::eek7: i just got finished rebuilding the motor and it runs great except the idel problem

Welcome to AF!

The IAC (Idle Air Control) valve needs to be cleaned or replaced and the throttle body needs to be cleaned. The air control valve lets small amounts of air into the engine to control the idle speed under different load conditions such as when you have the A/C on or an alternator or PS load. The chambers get excess dirt, oil from the air cleaner housing or carbon buildup.

To clean it disconnect the electrical connection and take the 2 bolts off. Pull it off being careful to not damage the gasket. Spray the 2 chambers with carburetor cleaner, let soak a few minutes, empty excess out and bolt it back in. You may have to run it with the throttle for the first few minutes to keep it running. Then it should stabilize. If this doesn't work you will probably have to buy a new one.

The throttle body gets a buildup of carbon, also. Hold the throttle plate open and spray with carburetor cleaner or throttle body cleaner. Put some towels underneath it to keep the spray off your fender. You may get a puff of smoke when you first start the engine. Don't spray it with any kind of silicone lube. It will coat the oxygen sensor and ruin it.

thank you for your help what does the iac look like and where is it and the throttle body is ther somewhere i can get a picture of them and wher they are i am old style car fixer the newer ones have to much pollution stuff so i do not know them enough thanks again:screwy:

I don't have a camera so it would be kind of hard to send you a picture. The IAC is on or close to the throttle body. It looks like a small motor with a couple wires running into it with a connector. It is about the size of a C cell battery. On the end there is a flat flange that connects to the throttle body bypass chamber. Look at your engine. You will have a long rubber connecting tube that runs from the air cleaner to the throttle body. This is your intake housing. The throttle body is between the intake housing and the engine. It is round and has a butterfly valve in it and is at the very end of the housing before it connects to the intake manifold. The gas pedal cable attatches to the throttle body. Have somebody step on the gas pedal while you are looking for it and you will see the location of the butterfly plate in the throttle body. The IAC is usually on the top of the throttle body. At least it is on my Escort.