5.4 2v miss. HELP!
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Senior User
Joined: Jan 2016
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From: South Arkansas
5.4 2v miss. HELP!
2003 F250. 6 speed. 5.4 2v. 4x4. 165,000 miles
When purchased, there was a vacuum leak and truck ran like crap and PO drove it that way for a while. I fixed the vacuum leak, discovered a miss between 1,500 and 2,000 rpms in every gear while accelerating. No miss at idle.
The truck has:
- no CEL
- new Motorcraft spark plugs that were not dropped, bumped, or over torqued.
- new fuel filter
- new air filter
- new alternator
*The miss usually does NOT happen in the morning on the way to work after sitting 14 hours.
*The miss almost always goes away after the truck gets up to operating temp.
*The miss ALWAYS is present after work on the way home after sitting 9 hours.
Fuel pressure?
Bad COP?
Fuel Injector?
Something totally different?
When purchased, there was a vacuum leak and truck ran like crap and PO drove it that way for a while. I fixed the vacuum leak, discovered a miss between 1,500 and 2,000 rpms in every gear while accelerating. No miss at idle.
The truck has:
- no CEL
- new Motorcraft spark plugs that were not dropped, bumped, or over torqued.
- new fuel filter
- new air filter
- new alternator
*The miss usually does NOT happen in the morning on the way to work after sitting 14 hours.
*The miss almost always goes away after the truck gets up to operating temp.
*The miss ALWAYS is present after work on the way home after sitting 9 hours.
Fuel pressure?
Bad COP?
Fuel Injector?
Something totally different?
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From: South Arkansas
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Mountain Pass
Joined: Dec 2010
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That sort of intermittent pattern would in the past have pointed to high tension leakage (i.e. from a plug wire), and it would not have been confusing at all, except that with high tension failure, you can get it to miss even worse at 1000 rpm under load than 1500. Back then, if you looked at the wires at night, you might see that they were bad. But in any case they were cheap, and it was okay to replace them once in a while anyway.
So in your case, it may just be the rubber hickey on a COP or a coil itself. Unfortunately, without a misfire code, you don't know which one to pull out.
So in your case, it may just be the rubber hickey on a COP or a coil itself. Unfortunately, without a misfire code, you don't know which one to pull out.
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From: South Arkansas
Firebird. Replaced coil boots today. On test drive I didn't notice misfire. Will see this week
Sam. Thanks for that info. I have actually ran across that before. I figured that's why no CEL has ever come on
Sam. Thanks for that info. I have actually ran across that before. I figured that's why no CEL has ever come on
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Senior User
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From: South Arkansas
Misfire stayed away for about 2 months.
I have a new misfire that is 1,000% random. Sometimes I make 3 trips in it with no misfire. Next trip it misses a time or 2 at low RPM. No miss for a trip, then a couple misses at highway speeds
Reminds me of old carbed junkers I used to drive
Now would a coil possibly be the problem?
I have a new misfire that is 1,000% random. Sometimes I make 3 trips in it with no misfire. Next trip it misses a time or 2 at low RPM. No miss for a trip, then a couple misses at highway speeds
Reminds me of old carbed junkers I used to drive
Now would a coil possibly be the problem?
Lead Driver
Joined: Nov 2008
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From: South Jersey
My 2004 2valve 5.4 has the same problem on and off for about a year now. Did new plugs and boots last summer and it seemed to go away. Just three weeks ago my boss started letting me take my work truck home so I only drive my truck maybe once a week now for a short distance. I know have a miss in gear under 1500rpm I can put it in N and reviews it a little and it goes away and then when I put her back in gear the miss comes back. I have no engine light either... I'm just tired of trying to fix it but these new vehicles need a real scanner so I'm just gonna let the local ripoff dealer check it for codes and I'll go from there
Junior User
Joined: Jan 2014
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From: Northern Va
Misfire stayed away for about 2 months.
I have a new misfire that is 1,000% random. Sometimes I make 3 trips in it with no misfire. Next trip it misses a time or 2 at low RPM. No miss for a trip, then a couple misses at highway speeds
Reminds me of old carbed junkers I used to drive
Now would a coil possibly be the problem?
I have a new misfire that is 1,000% random. Sometimes I make 3 trips in it with no misfire. Next trip it misses a time or 2 at low RPM. No miss for a trip, then a couple misses at highway speeds
Reminds me of old carbed junkers I used to drive
Now would a coil possibly be the problem?
had the same problem with my 02. felt like a miss at random times turned out to be my fuel pump was bad.
Senior User
Joined: Jun 2015
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From: elkmont alabama
could possibly be a coil that is trying to go out. get a spark tester test the coils to see if you can spot the miss. before I got my f250 with the 5.4 2v my father in law said it had a miss and it would come and go almost like yalls but it was everytime anyone drove the truck after some testing it was the number 4 coil pack that had gone out
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