Help me troubleshoot my 2004 f150?
03-29-2010, 07:11 PM
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Help me troubleshoot my 2004 f150?
Hey folks...this'll be my first post on yalls board, so I figured I'd jump right into the "help me" thread...
I've had my CEL on for...awhile...but being out of work, I just didnt even wanna check what the codes were (seeings as how I didnt see myself being able to afford the fix). After I got work again, I decided the truck would be the first thing I messed with, so I ran down to autozone and had them all dumped: Lean on bank 1, lean on bank 2, misfire before 1000 revs, misfire on cylinder 3, bad MAF.
I sprayed down my MAF with MAF cleaner and the code went away...changed my plugs and wires (was after 100k miles anyway), and my fuel filter (also 100k miles). No real change.
The truck idles roughly and when I gas it hard, it bogs down and knocks. On the highway I cant get above 70-75 or so...if I load the engine hard the CEL flashes, but if I'm gentle I can keep it from doing so.
Pulled the #3 plug (a number of times) and finally decided the spark was weak...put in a new coil pack. No change.
No vacuum leaks (that I can find), and a new PCV valve/hose. Still nothing.
Bought a fuel pressure test gauge...getting 32 PSI on the fuel rail when the truck is running...under acceleration it surges up to 38 or so, then back down to 32. When the truck off, the pressure seems to remain constant for as long as I looked (5 minutes or so), even though it was 0 PSI when I first plugged in the gauge (didnt run the truck for a few days).
So...any ideas what to check next?
--edit--
2002 Ford F-150, 4.2L V6.
I've had my CEL on for...awhile...but being out of work, I just didnt even wanna check what the codes were (seeings as how I didnt see myself being able to afford the fix). After I got work again, I decided the truck would be the first thing I messed with, so I ran down to autozone and had them all dumped: Lean on bank 1, lean on bank 2, misfire before 1000 revs, misfire on cylinder 3, bad MAF.
I sprayed down my MAF with MAF cleaner and the code went away...changed my plugs and wires (was after 100k miles anyway), and my fuel filter (also 100k miles). No real change.
The truck idles roughly and when I gas it hard, it bogs down and knocks. On the highway I cant get above 70-75 or so...if I load the engine hard the CEL flashes, but if I'm gentle I can keep it from doing so.
Pulled the #3 plug (a number of times) and finally decided the spark was weak...put in a new coil pack. No change.
No vacuum leaks (that I can find), and a new PCV valve/hose. Still nothing.
Bought a fuel pressure test gauge...getting 32 PSI on the fuel rail when the truck is running...under acceleration it surges up to 38 or so, then back down to 32. When the truck off, the pressure seems to remain constant for as long as I looked (5 minutes or so), even though it was 0 PSI when I first plugged in the gauge (didnt run the truck for a few days).
So...any ideas what to check next?
--edit--
2002 Ford F-150, 4.2L V6.
Last edited by KenRocks; 03-30-2010 at 01:22 PM.
03-29-2010, 07:16 PM
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Turn it off and wait till something breaks.. then replace it lol j/k.. I dunno I have an 04 and i've never had this problem yet, im approaching 100,000 miles... sounds like you had alot of fun with that truck.
03-29-2010, 07:27 PM
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Haha...only in the last few months. For the 3 or so years I owned it (used) before then, it worked flawlessly and I'm awful to my vehicles 
Just found my manual...apparently I should read 50 PSI for key on, engine off. I have 30-32 PSI. For engine running, it should also read 50 PSI. Still 32.
Maybe Im close to something...but how do I narrow down exactly which fuel system component this is without dropping my fuel tank to get a new pump and realizing the old one's fine...
Just found my manual...apparently I should read 50 PSI for key on, engine off. I have 30-32 PSI. For engine running, it should also read 50 PSI. Still 32.
Maybe Im close to something...but how do I narrow down exactly which fuel system component this is without dropping my fuel tank to get a new pump and realizing the old one's fine...
03-30-2010, 01:23 PM
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And I'm dumb. Truck is a 2002, not 2004. Original post edited to reflect this.
Also, the numbers in my book only apply to 4.6L engines...I think I might have the wrong pressure values. Does anyone know what its supposed to be on a 2002 4.2L V6?
Oh...and I guess my mistake on the year puts this in the wrong forum...can a mod give me a hand...?
Also, the numbers in my book only apply to 4.6L engines...I think I might have the wrong pressure values. Does anyone know what its supposed to be on a 2002 4.2L V6?
Oh...and I guess my mistake on the year puts this in the wrong forum...can a mod give me a hand...?
