Hi Guys,

My F150 at startup is reving real high, almost max rpm's, like the pedal is on the floor. Any idea on what could be going on?

Thanks, John

 

IAC probably bad or something is blocking the accelerator from going to back to the idle stop.

 

Thanks for the reply,

Where would you start? Is there a DIY for the IAC? I haven't worked on my 150 yet, is it something not too difficult to replace?

 

First thing to check is the throttle stop area when cold.
It's under the shrould where the throttle cable connects to.
If you have Cruise Control, look at the possabilty of that hanging the throttle off normal.
If it's all free for movement, remove the Intake Air Controller (one with the electrical connector on it) right there on the throttle body and use Throttle body spraycan cleaner inside until it comes out clean and be sure the pintle moves freely inside the hole.
.
The normal operation is too high idle the motor for cold starts depending on the ambient temperature.
High idle in summer should be no more than about 1200 rpm, then lower in a few minutes to about 650.
If you still have an issue after this, then you have a major air leak, likely a rubber fitting on the intake at some location that admits unaccounted for air until it gets warm and closes up.
I would not use the truck untill you solve the issue, for safety reasons.
Good luck.

 

Thanks again,

Perhaps I should mention the high rev remains high, it never lowers itself, I can't even keep the engine running for more then a few seconds since I'm afraid to damage the engine.

John

 

Do not start it until you've done all of the visual checks mentioned above!

 

If it's that bad, the throttle plate is stuck open or a massive air leak is present.
The other items should not act to that extent.
Also check that the throttle body and it's housing down to the intake is not loose.
Good luck.