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07 F-150 5.4 Triton misfire then no power at all


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ipfreely02
New User

Feb 12, 2024, 9:16 PM

Post #1 of 5 (17192 views)
07 F-150 5.4 Triton misfire then no power at all Sign In

 I have an 07 F-150. There has been a misfire occurring with my truck. I have changed plugs and a few coil packs. It has a new fuel pump and fuel lines. Unfortunately, it still misfires. I mixed seafoam into my gas and that also did not help. I was heading to work and my truck dropped rpms and lost power. It will roll over but fails to actually stay running. When it first cranks up, it spits and sputters then dies. Everything i researched pointed to the crankshaft sensor. That has been replaced. Still doing the same thing. Tomorrow i am going to hook a scanner up to the computer and reboot the sensor to relearn the engine pattern. If this does not fix the problem does anyone have any recommendations?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 13, 2024, 5:47 AM

Post #2 of 5 (16896 views)
Re: 07 F-150 5.4 Triton misfire then no power at all Sign In

Stop throwing parts at it and do some testing starting with the fuel pressure. There is no sensor to reboot. Don't disconnect any batteries or try to reset anything because all you would be doing is erasing valuable stored diagnostic data in the computer.

If you can get your hands on a professional scanner, not a generic code reader, you can look for any data out of parameter. You should also have a code/s specifying which cylinders were misfiring.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



ipfreely02
New User

Feb 13, 2024, 11:58 AM

Post #3 of 5 (16624 views)
Re: 07 F-150 5.4 Triton misfire then no power at all Sign In

Update: The power steering switch is also bad. Both are on the same 5 volt circuit. The guy literally unplugged the power steering switch and the damn truck ran and drove fine. Crazy something that minuet can cause engine failure.


ipfreely02
New User

Feb 13, 2024, 12:10 PM

Post #4 of 5 (16612 views)
Re: 07 F-150 5.4 Triton misfire then no power at all Sign In

Thank you for your help. I used a professional scanner previously and fuel pressure was weak. That’s why I changed the fuel pump and lines. (That fixed that problem)
My truck has 250k miles. My dad still has a 93 F-150 with over 350k on it and he knows it inside and out. Like he says “on those older trucks everything was black and white. You could pin point the problem and fix it”. Without a scanner you're in a bind with newer vehicles.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 13, 2024, 1:09 PM

Post #5 of 5 (16562 views)
Re: 07 F-150 5.4 Triton misfire then no power at all Sign In

Every time I hear someone complain about how complicated and hard to work on new vehicles are I use this example.

In your 1960s or 70s vehicle with no computers, could you walk up to your vehicle in sub zero temps and reach through the window to turn the key and start the vehicle without getting in and have it sit there and idle perfectly?

No, you couldn't so before you say how hard computers have made cars to work on, think about all the benefits and comforts you have gained because of them.

And don't forget the fuel mileage. My 1970 305 Chevy used to get 10MPG with 200HP. Now you can get 400HP and 25MPG.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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