1991 Ford E-Series Van idle I NEED HELP

LMARKVIII

MEMBER
1991 FORD E-SERIES VAN

Engine Performance problem
1991 Ford E-Series Van V8 Two Wheel Drive Automatic 100k miles

I am having problems with the idle on my van it has a 302 in it. I recently had the frame rail fuel pump replaced. And after that I started having problems with the idle. When I start it in the morning it starts to idle up when I catches itself and levels off before going high enough. Then when starting to drive when its cold it stumbles a little. Then once warmed up it will run ok. Then after driving when I put it in park it idles down and just dies. It doesnt run rough or anything its like I just turned off the key.
I did replace the iac about 5k ago. If I recall correctly the symptoms are the same as the last time.

I think that the shop who diagnosed the fuel pump problem may have sprayed starting fluid in it possably messing up the iac. Am I correct im assuming that this is a possability? I have heard of this before but not sure if it is correct.

I am sorry guys about the lack of a donation but guys I have thrown so much money into this van already im just about broke the fuel pump escapade was 540.00 that was a week ago and I still owe for it sorry again. I would really appriciate any help you can give to prevent me from having to go back to shop

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Take the idle air control valve back out and clean it and see what happens

Here's how to clean the IAC valve:

Disconnect the air intake ductwork from the throttle body.

Start the engine, then increase and hold the idle speed to 1,000 to 1,500 rpm.

Spray the throttle cleaner or engine cleaner into the throat of the throttle body, aiming for the idle air bypass port (usually located on the side or top of the throttle body opening). Give this area a good dose of cleaner (about 10 second's worth).

Turn the engine off to allow the cleaner to soak into the IAC passageway.

Wait about three minutes.

Restart the engine, rev and hold at 1,000 to 1,500 rpm, and repeat the cleaning process again.

Turn the engine off again, and reattach the air intake ductwork to the throttle body.

Start the engine and rev and hold to 1,500 to 2,000 rpm until no white smoke is coming out of the exhaust pipe.

If this fails to make any difference, you can remove the IAC valve from the throttle body and spray cleaner directly on the tip of the valve and/or into the ports in the throttle body. Let the cleaner soak awhile, repeat as needed, then reinstall the IAC valve, start the engine and run it at 1,500 to 2,000 rpm as before until no white smoke is seen in the exahust.

If the idle speed still surges after this, the IAC valve is defective and needs to be replaced