Hesitation on acceleration

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Sep 8, 2009 | 05:55 PM

Ben Marshall

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From: New Mexico

Hesitation on acceleration

OK, I have the 2000 Expy 5.4 and it has an occasional hesitation. I have watched it for a while and have noticed the two things that seem to affect it is temperature outside and idling. It runs great if it is about 85 degrees or cooler, but if it is hotter than 85, it hesitates and stumbles, and the hotter it is, the worse it gets. It also seems like idling makes it even worse. On a hot day, if I let it idle for more than about 5 minutes, it stumbles real bad when I accelerate. I have searched on here and most of the threads and symptoms point to cops, so I changed them all out. I have also changed out the plugs, fuel filter, PCV, and I cant find any vacuum leaks. I just read on one thread about the ac condensor leaking on the O2 sensor, which would make sense, since I run the ac anytime it is over 85 degrees. Im going to check that out tomarrow, but is there an other suggestions? Thanks

Sep 8, 2009 | 06:02 PM

alloro

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Since the problem seems to be heat related, the coolant temperature and air intake temperature sensors come to mind.

Sep 8, 2009 | 11:45 PM

Ben Marshall

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From: New Mexico

ok, weird, I thought I replied to this, but apparently everything was lost...hmm.. anyway, It doesnt seem to be related to engine temp, just ambient temp. I did replace the intake air intake temp sensor (I think that was my first repair), but havent thought much about the coolant temp sensor.... could it be wrong? The gauge on the dash reads normal, but what is the actual coolant temp supposed to be? I do have a temp probe I can stick in the coolant to get the actual temp of the coolant, but I dont know what the coolant temperature should be. BTW, I am starting to think about the Yukon, even though they have the gps tracking thing, I am starting to loose my faith in Ford.

Sep 10, 2009 | 10:28 PM

Ben Marshall

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From: New Mexico

Would, by any chance, the PCV valve cause this kind of problem? I was messing around with it tonight and notice the pcv valve was bad. I changed it out, but now its cool outside and it is running fine. I will test drive it tomarrow when it is hot again, but I was sitting here bored and was wondering what everybody thought. And, just to let everbody know (Im kinda proud about it and am telling everyone I know) Im the proud parent of a new baby born on Sunday. He is a baby boy born at 7 pounds 15 ounces 20 3/4 inches, and is healthy as an ox.

Sep 11, 2009 | 10:18 AM

alloro

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Quote:

Originally Posted by Ben Marshall

And, just to let everybody know (I'm kinda proud about it and am telling everyone I know) I'm the proud parent of a new baby born on Sunday. He is a baby boy born at 7 pounds 15 ounces 20 3/4 inches, and is healthy as an ox.

That's awesome...have you found the father yet?

Sorry just kidding.

Seriously though, congratulations. First one?

Sep 11, 2009 | 05:13 PM

jjcast

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From: florida

wont hurt to replace the PCV valve, i had exactly the same issue with my 2001 5.4L ended up being the IAC valve which is a total bitch to get to... took all afternoon but fixed it right up.