2003 5.4L Quits

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Dec 20, 2009 | 08:14 PM

Planenut99

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2003 5.4L Quits

Hello all, I'm a newbie looking for some help. I have a 2003 F350 crew cab with a 5.4L.

Occasionally, when you stop, the truck idles slightly low and quits when you attempt to accelerate.

I have changed the fuel & air filters, installed new spark plugs, replaced one bad spark plug boot, cleaned the mass airflow sensor, cleaned the throttle plate, checked the fuel pressure, and verified the system voltage.

The truck has not set any codes or pending codes. I called and spoke with a tech at the local Ford dealer and he has one in the shop with the same problem. They had replaced an idle air control and the truck came back. He is stumped as well. (my competitive side would love to figure it out first!)

Anyone have any ideas?

Thanks in advance!!
Jeff

Dec 20, 2009 | 09:14 PM

ReAX

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From: Central Florida

Have you cleaned the IAC or DPFE valve? IAC or other vacuum leak would be my top suspects.

Dec 20, 2009 | 09:24 PM

aphotic26

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Check the hose that connects to the PCV to the back of the throttle body it will most likely have a foam sleave, you can slip that off and check the plastic hose for cracks...

Dec 20, 2009 | 10:18 PM

biz4two

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From: Albuquerque

Def sounds like an IAC or vacuum leak. Good luck...

biz

Dec 21, 2009 | 08:39 AM

scraprat

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From: Itinerant

Have you disconnected the battery for awhile?

Dec 21, 2009 | 05:38 PM

Planenut99

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Thanks guys,

Sorry but I wasn't at work today and it looks like I have a broken roller to attend to tomorrow. I'll take a look at the vacuum lines you mentioned and let you know. Is there a cleaning procedure for the IAC?

Dec 22, 2009 | 12:27 AM

biz4two

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Joined: Sep 2003

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From: Albuquerque

Take a look at my gallery (see link) for IAC info...

2003 Ford F250 4x4 - V10 IAC

When you remove it...you can clean it with MAF sensor cleaner or carb cleaner. Just be careful and let it dry complete before reinstalling. You prob going to need a new gasket too.

IMO...if you are going this route, then just replace it. This is not a high price item...

Good luck...

biz

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