99 5.4 Expedition

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Oct 10, 2004 | 03:49 PM

Wthomaslee

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From: Malvern AR

99 5.4 Expedition

Don't know if this has been posted or not but this is my first time with this site. I have a 99 5.4 Exp. and it has developed a problem. Sometimes when I start it dies right away , it dose this 3 or 4 times before it stays running. Also when I try to maintain a speed it has a miss or missfire. It feels like a bad fuel filter but that didn't help. I pulled random plugs and they look great, no vac leaks that I can find , and all the coils check out by my ohm meter... Any help would be greatly appreciated.

Oct 10, 2004 | 05:28 PM

Wthomaslee

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From: Malvern AR

forgot to list more info

Ohh, also the first time it did this, the check eng. light came on and the Ford place said that they could not extract a code so they cleared it. The light has not came back on but the problem persist.

Oct 10, 2004 | 11:37 PM

bfr

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It's probably your IAC valve. Do a search,you'll find plenty of info.

Oct 11, 2004 | 05:03 AM

BigMan69

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From: Long Island, NY

Sounds EXACTLY like the IAC Valve (Idle Air Control Valve). They are notorious for going bad at about 50,000 miles. Pretty easy to change and part is about $65 unless you are under an extended purchased warranty.

BigMan69

Oct 11, 2004 | 04:38 PM

Wthomaslee

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From: Malvern AR

made it worse

I replaced the IAC valve and cleaned all the gunk off everthing and it ran lots better, lots more response and felt like a million bucks power wize. Then just when I thought all was fixed a dead miss developed on #2 cyl. going to let it cool till tomorrow. Going to check plug and cop. hope one of the two is bad so it can't be anything else. any ideas?

Oct 11, 2004 | 11:15 PM

buzzard

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Probably just the COP or its boot. Get your replacement parts from NAPA or other part store and save 50%.

Oct 13, 2004 | 05:28 PM

jprop

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Check for a vaccuum leak on the rubber elbow at the extreme back of the engine. It is extremely difficult to see but you can feel it. It is the vaccuum source for the PCV valve. This elbow rots away after a few years and will cause the symptoms you describe. It takes about three minutes to check it and 10 minutes to replace it.