Engine miss under load

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Jul 13, 2010 | 08:54 AM

Downriver Thunder

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From: Wyandotte, Michigan

Engine miss under load

Got an issue with a big time engine miss under load that sprang up a couple weeks ago and it's getting worse. 05 250 5.4L FX4, 114519 on the clock. When driving down the road and the trans shifts up to highest gear everything is fine until I need to get more speed. I will give it the gas but not enough to where it downshifts and then all hell breaks loose. It feels like you're on a street of really bad potholes it misses so bad. When it first started it was an occasional miss, now it's steadily getting worse. Any ideas? New air/fuel filters about 6mos ago.

Jul 13, 2010 | 08:56 AM

Downriver Thunder

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From: Wyandotte, Michigan

Oh, normal driving you can't feel any sort of miss at all, only under a load it seems.

Jul 13, 2010 | 06:56 PM

trimman

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From: Moriches USA

Sounds like a COP, do a search here

Jul 13, 2010 | 07:05 PM

Fordfanatic4life

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From: Richmond BC

yea plugs fouled/over-gapped, or COP's going bad..

funny you should write this post. my truck is just starting to hint at trouble, power is down, it seems to struggle under load, no bucking/lurching thou..

i think its time for all new plugs/COPs/boots.. my truck has 220K miles, and i have no idea if the COPs are original or not..

Jul 13, 2010 | 09:53 PM

Robs06SuperDuty

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From: Gettysburg, PA

yup more than likely its a COP, my 06 did the same thing with 58K on the clock so I had the COP fixed under warranty and then at my 60K mile service I had the plugs changed, the gaps were wayyy out of spec. it definately needed new ones. but since then I havent had a problem and I have almost 70K on it now.

Jul 13, 2010 | 10:59 PM

EXv10

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From: Mt. Shasta California

Water in your spark plug holes will do that too.

Jul 13, 2010 | 11:02 PM

Robs06SuperDuty

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From: Gettysburg, PA

Quote:

Originally Posted by EXv10

Water in your spark plug holes will do that too.

when I took my truck in for the COP (#7 cylinder) it had water in the spark plug hole hense the reason it failed. it was back in the winter right after we got a lot a freakin snow.

Hey Ford... put freakin drain holes in the heads for water n dirt to drain out of... wait thats too smart lol