I have a '00 F-250, 5.4L. Most of the time, the truck runs fine... HOWEVER, sometimes it just won't hold a normal idle. When this happens, the truck will idle around 400-500 rpm. Once the problem kicks in, it will remain for days. Sometimes, while this problem is happening, I could be sitting at a light and the engine will suddenly surge back to a normal idle. It's like a solenoid will suddenly click in. Does anyone have a suggestion as to what might be causing this problem???

Thanks,
Dave

 

Any DTC's/CEL??

Check the IAC motor, if 'unplugged' the idle 'should' drop on a stable/spec. RPM,, if no difference on a lower idle or below spec.condition, thanthe IAC may bea fault, andfor a stuck/sticking EGR.. Try unplugging the vacuum hose on the EGR diaphram as well during an idle issue to see if EGR is being applied and not actually a valve issue.. Both can generate a lower than Spec idle... These would be 2 items I'd check straight off..

1. IAC
2.EGR

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I could not agree more IAC it probably is, if not you waisted $65, then my next guess would be a possible mass air flow sensor, but the IAC makes more sense.

 

To all that may read this... and to the two kid people that had replyed to my request...

Just wanted to say "Thanks". I just replaced the IAC and believe that was the problem. The old one was near "COMPLETELY" blocked. The new one had no problem passing air through.

I replaced it and the truck seems to start and run fine.

Hope this solve will help others... :-)

 

Glad to hear. Oh yeah what was the price? Was I close?

 

$39 @ Pepboys. What a deal.

 

I need to replace my IAC for low idle problems. I purchased a new one but can't locate the old one on the eng. I have a 2001, F250, 5.4L 4x4. I looked at Hayapowers thumbnails but need more specific instructions. Can anyone Help. Thanks...

 

Look on the backside of the intake elbow/throttle body..

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Thanks, I'll check it out.