I have a '91 Aerostar with a 4.0L engine that dies at stops while it's cold. I have cleaned the throttle plate body and cleaned the MAPP sensor but it didn't fix it.

Does anyone have any suggestions for a fix?

 

I'd clean or replace the IAC valve next. It's a typical failure on fords.
Often times idle is inconsistant, fast, slow, or the motor dies if your not pushing the gas. Motor runs smooth otherwise.

Rich

 

Where is the IAC on the 4.0L?

 

It should be right behind the Throttle body on the driver side.

 

Ok, pulled the IAC and cleaned it with carb cleaner spray. It did help it so I will pull it off again and try to get all the carbon off the valve and seat. I figure if I can get it real clean it will be like new. Nothing to loose and money to gain if I can get it really clean.

Thanks for the info.

 

No problem.

I've personally cleaned them and still would not work much better. Wound up replacing it and then the motor ran perfectly. (94 T-Bird)

Ever since then I keep mine as clean as a whistle. Usually pull it off every 10k miles and give them a little spray. No problems when I do that. (all my fords)

Rich

 

Yes, letting the carbon built up to long is a bad move.

I pulled it off just now and removed the solinoid coil and the oring and used carb spray and a pipe cleaner to clean it more. I rolled the pipe cleaner around the valve seat area and got a lot of carbon out. Blew it out and assembled and installed and test drove and it is almost perfect now with a slight hesitation.

My wifey decided we have to go somewhere at 3 PM so I will take it off, tear it down tomorrow and soak it in some real carb. cleaner I have. It's some powerfull stuff and will eat the carbon out. I think I can save this IAC.

I think I will look at my lil' Ranger's IAC and clean it out. It has about 62K on it and may be carboned some.

 

Glad to hear it's something simple and cheap. That's usually not the case in life.

 

Ok, just got it cleaned up and back together. There is two chambers in the IAC on the '91 and I cleaned both in the carb cleaner for about 3 hours. Flushed with water and then used the spray carb cleaner to flush everything. Put it back to gether and now the engine has a slight hesatation but don't die at take off from stop but the temp is only about 45 degF so I will wait for colder days.

Since this a back up vehicle I'll probably leave it alone but if it was my main ride I would replace the valve since as others have said, just replace it. Cleaning one that is already giving trouble will not solve the problem.