How do you get rid of that fast idle at start up crap?

[hotkarl]

Been doing it for years, but it's finally starting to really annoy me.
Only does it for a few seconds when you first start it up, but it's driving me nuts now. Is there an easy fix for this?

 

[shadowless127]

What exactly do you mean by "fast idle" ?

 

[hotkarl]

When it first starts it's like you're holding the pedal to the floor.
Revs like a ******* for the first 3 seconds or so and kicks down to what I would consider a normal start up idle.

 

[Runnin'OnEmpty]

Do a search for 'fast startup rev or idle' and you'll see
posts from several years back on this topic.
We tried lots of things to lower the startup revs, with
limited success.

I finally inserted a section of fuel hose in the IAC valve,
to restrict the maximum airflow allowed through the valve.
This helped reduce the revs a couple hundred; not enough
but better.....

This startup rev is programed into the PCM so it's not
easily adjusted out.

 

[shadowless127]

That sounds like Deisel engines High Idle.

Is this restricted to just 4.0L OHV's? None of the 5.0 X's I've been around have done this.

 

[Joe Dirt]

My 4.0L OHV has never sounded like I've got the pedal matted for a few seconds when I start the truck. Your truck idles at 3-4k?! That isn't how it's supposed to be- something is wrong. Codes?

 

[shadowless127]

My 4.0L OHV has never sounded like I've got the pedal matted for a few seconds when I start the truck. Your truck idles at 3-4k?! That isn't how it's supposed to be- something is wrong. Codes?

I was thinking the same thing. I have the OHV in my 93 (obviously) and it's NEVER idled passed MAYBE 1500rpms in 5-10degree weather.

 

[hotkarl]

I wouldn't say 3 or 4K, but around the 2-mid 2K area, and it is literally for a second or 2, just as soon as it turns over. It then immediately kicks down.
Got 130K on it. Little by little the Gremlins are starting to make things happen...

 

[sicktight772]

mine does it too. I have an 98 4.0L SOHC. Nothing to do but to try to ignore it.

 

[mechanix]

A lot of Fords do this especially in colder weather. If the ect sensor reads below a certain temp it will high idle the engine for a bit, it just helps when starting and also decreases the time the engine takes to warm up. Like others have posted it is built into the PCM so there is really nothing that can be done. You might want to look at some intake gaskets or even the cleaning the IAC if you think it is something mechanical.

Good luck

Eric