5.4 sd missing under load
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5.4 sd missing under load
was told to start a new thread , so here it is , my 2000 f-250 sd 5.4 misses under any kind of load , idles pretty smoothly but any load , such as pulling a hill , it misses badly , i've already changed the plugs , boots , coils ,and still have the problem , also reads out no codes. the thing that i dont get is on the scanner ,while driving , i noticed that the timing retards under load , as far as going back to zero(base timing),it has 153,000 miles on it if that makes any difference,any suggestions? i have checked fuel pressure , i have about 30-35psi with the vaccuum line on , about 45-50 with the line off
Last edited by turk1124; Aug 17, 2007 at 09:36 AM.
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From: Stephensville WI
Does your scanner read pending codes? It sounds like you still have a bad or weak COP that is misfiring.
Otherwise, it could possibly be a fuel injector that is partially clogged, but from what I have seen on this board most misfire problems are COP related.
Otherwise, it could possibly be a fuel injector that is partially clogged, but from what I have seen on this board most misfire problems are COP related.
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From: Stephensville WI
No.
To get a misfire code, a cylinder has to misfire X number of times in a certain period. If that doesn't happen, you won't see a Check Engine Light and won't have a code, but the pre-codes will be there if you can get them read.
To get a misfire code, a cylinder has to misfire X number of times in a certain period. If that doesn't happen, you won't see a Check Engine Light and won't have a code, but the pre-codes will be there if you can get them read.
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From: Stephensville WI
You're looking for a code like P030X, where X=the cylinder that is misfiring.
https://www.ford-trucks.com/article/idx/7/0/
A list of the codes.
https://www.ford-trucks.com/article/idx/7/0/
A list of the codes.
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Tuned
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i had the same problem with my 5.4 after i sucked k&n filter oil up the intake (long story), it ran fine and smooth idling but under any load it misfired. shorted out the MAF IAC and TPS, then about two weeks later my exhaust O2 sensory went. don't know if there is any correlation between the two, but after i replaced the o2 sensors it runs great and haven't had a problem since. by the way i never threw a check engine light that whole time either.
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still having problems , now what happening is that when you try to read codes from the scanner , even making faults( unplugged coils ,injectors ,) and it still dont pick up any codes , tryed the scanner on another truck and did the same test(unplugging something to make it read a code), and it picked up the codes right away , can the computer be at fault? is it possible to have the computer tested ?
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alright now , i have had the computer reflashed , and still no trouble codes and the miss is still there, i even unplugged a coil and an injector while it was running , and still no codes were picked up , whats next?
