5.4 Missing Until Warm

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Oct 25, 2010 | 07:51 PM

HammeredFlat4

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5.4 Missing Until Warm

Hey guys I have a 99 F250 with a 5.4. Recently it started missing so I replaced all the coil packs and spark plugs. It ran great the first couple times I drove it afterward but now when I start it up in the morning when its cold it idles fine for about the first 5 seconds and then it starts missing, after about 5 minutes it goes away and runs perfect for the rest of the day. Anyone have any ideas this is driving me nuts!?

Oct 26, 2010 | 01:14 PM

HammeredFlat4

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No one has any ideas? I used Granatelli COP's and E3 spark plugs. Could it be my IAC, maf, or o2 sensors?

Oct 26, 2010 | 09:32 PM

HammeredFlat4

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Ok I went and bought a code scanner and here are the codes it spit out.

P0351
P0353
P0354
P0355
P0356
P0302
P0305
P0306

1 I/M EVAP

Oct 27, 2010 | 12:43 PM

HammeredFlat4

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Oct 28, 2010 | 06:14 AM

torkum

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First check the wiring harness to the cops. Next might want to go with motorcraft plugs and cops.

Jan 11, 2011 | 05:15 AM

Synsterf250

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I`m dealing with the samething ..

Mine just started yesterday. i`m hope someone will be able to help .

Jan 11, 2011 | 05:28 AM

JWA

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From: Reynoldsburg, Ohio

Quote:

Originally Posted by torkum

First check the wiring harness to the cops. Next might want to go with motorcraft plugs and cops.

I three am having something similar---codes show misfire on Cyl #7 of the 5.4 V8. I suspected a bad #3 COP wire harness connector as this has happened before on that cylinder however previously it was the COP itself. Changed the #7 COP and problem persists so next up it changing the harness connector; NAPA part number EC259 for a cost of about $20 each.

Seems odd this happens when winter sets in---wonder if it could possibly be related or just coincidence?

Hammered I don't know which scanner you bought but I have the Actron CP9580 with something called "Code Connect" which gives the top reported fixes for any code discovered. This isn't always spot on but it does give an idea of where to begin looking. It also clears codes so you can check your repair with something more than a feeling all has gone well.