#1 and #3 misfiring please help - Ford Powerstroke Diesel Forum
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post #1 of 3 Old 03-11-2008, 09:00 AM Thread Starter
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Unhappy #1 and #3 misfiring please help

I have a 01 f350 with 7.3 It has 140,000 miles on it. It start missing and finally would not start. I have replaced the electric fuel pump and filter and cleaned out the tank and lines. Truck will start now but is still missing. I took it to a buddy of mine and ran a buzz test. It says #1 and #3 cylinder misfire. I put in 2 new injectors and still missing. Sometimes the buzz test says test pass and sometimes #1 and #3 and sometimes 1,3,5,7 misfire. I have changed out both computers and tried a new wiring harness for the injectors. I'm trying to check the wiring to the computer now. Should I just buy a new harness or could it be something else. Please Help I need the old girl @ 100%
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post #2 of 3 Old 03-11-2008, 11:56 AM
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man you just put a lot of money into your truck. try the CPS sensor did you do the recall yet. thats akk it might be

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post #3 of 3 Old 03-12-2008, 03:59 AM
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If you've swapped injectors and it's still missing, it's got to be electrical. Start with the under-valve cover wire harness (looks like you did), then the actuall valve cover gasket (the plugs go bad), then IDM & PCM (looks like you did). If that doesn't work, trace the wires. Got to be a pinched or broken wire in the harness.
Good luck.

An OBS or 2, or 3...
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