Idle problem

[kenshin5.0]

Hey, I have a 1990 5.0 that will not idle when you first start it up if you run it down the road a while it will start to idle. But then if you shut if off for more than an hour it has the same problem. I bought this car about two years ago and the guy said all he ever did was headers and mallory ing. system. Any help would be great.

 

[Rick 91GT]

Id start by cleaning your IAC valve (attached to the front side of the TB), also clean the throttle blade area in the throttle body.

 

[4rdnut]

When you run it down the road and it finally idles, is the idle real low? If it is then just raise your idle.

 

[Mustang5L5]

Moved to 5.0 tech for more visibility.


Start by cleaning the IAC. Next, perform the base idle reset procedure.

If that doesn't help, drive for a day or so and then run the check engine codes.