i have a 2003 5.4 sometimes it doesnt start right away, it turns over and when it fires it sound like it stumbles like there is too much gas not all the time but enough could it be the iac valve?

 

Maybe. It could also be other things, such as weak fuel pressure.

More diagnostics are defintiely needed.

Steve

 

...Welcome glenny to Ford Truck Enthusiasts!


…..See you on the boards.

 

ive had a rough idle since new so from what i read i thought it could be iac valve. if it was a weak fuel pressure wouldnt it do it all the time?

 

Not necessarily.

You might have a clogged fuel filter that is delaying the application of full pressure.

Might also have a faulty check valve on the pump that is allowing the fuel pressure to bleed down.

Try cycling the key to RUN but not hitting START. Switch OFF. Repeat several times, they try starting. See if that makes any difference.

Try cracking the throttle while starting. If that helps, the IAC is sticking closed.

Any CEL/SES? You didn't state. If so, get codes.

Steve

 

Check when you open your truck's doors if the chime is going. Even though your lights maybe off and no key in the ignition.