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fuel pressure falls when driving.

1209 Views 2 Replies 3 Participants Last post by  TexasBlownV8
stock '05 v6, sky blue (it's invisible to police radar)

replaced fuel pump, fuel filter (seriously needed it and i didn't know), and fuel pressure sensor.

will start and drive for some amount of time, average about ten minutes give or take, before bogging down and stalling out. loses power (code indicates low fuel pressure) when stomping on the throttle. idles very rough sometimes but not all. battery, alternator check good.

my mechanic (i just didn't want to do it all myself even though i could have) finally had to throw in the towel and said he wouldn't charge me since he couldn't fix it. we took it to another shop that specializes in automotive electronics, or so the sign implies.

$50 later they tell me it's either the computer (pcm?) or a wiring short/open. they said the next step is to pull the harness off the computer and check for erroneous voltage with the ignition switch off at both the computer and the wiring harness. if there is erroneous (as in not supposed to be there) voltage at points on the computer connector then i have a bad computer. if the erroneous voltage is in the wiring connector and not at the computer then there is a short or open somewhere in the harness. either way it's interfering with the fuel flow in my pony and i don't like that.

end result, if you're still reading this, which is it most likely to be? the computer or the wiring? or did i completely misunderstand what i was told the next step in troubleshooting should be?

now for the sob story- i've been borrowing a friends car for over three weeks and i really don't want to impose on her (it's her only car) any more than i have to. i can afford a computer next payday (i could afford one out of a junk yard just to get by even more) but either way, i need to get my girl running asap. any and all help will be greatly appreciated. and no, i can't afford the airfare to come and give you a hug, but if you're in huntsville alabama i'll buy you a beer in lieu of a hug. i'm really not a hugger.
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Don't we have a fuel pump "driver"? anyone check that out? It is my understanding that it regulates the fuel pressure by raising or lowering the voltage, very well could be the culprit.
What code(s) are you getting?

Don't think the pcm nor wiring is your offer. But post up the codes and we'll see what else we can figure out.
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