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arielleon90

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arielleon90 Enthusiast

arielleon90

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So this past weekened decided to get my truck checked. Lack of power. And well mechanic checked it put on the scanner. Has a misfire on cylinders 4 and 5. So we go on get the coils checked switched those around. Still has the same cylinders misfire. So next we check compression but that checked out good. Next we check fuel pressure first we checked each injector on its own (didn't know you can do that but he had a fancy scanner) but those checked out fine. Next we move on to the fuel regulator which he said it worked fine (How can I check it to be sure?). So after all that checked out we were stumped well at least I was. We turn on the truck with the pressure gauge still connected n bam fuel pressure jumps up to 90-95 psi. In my head I'm like even I know it's not right. So that lead us to the bottom of the truck turns out the return line had been squeezed. He said the previous owner probably wanted to avoid the hassle of taking the gas tank down and replacing the pump. So he replaces the squeezed line and put a rubber hose in place (fuel hose) at first the truck was still running rough. But after a drive home it went away so I thought it only lasted a day and started running rough again. Now I'm back at square one.

 

My question is thou what do I do next replace those 2 injectors, replace fuel pump, replace fuel regulator?

 

I forgot to mention after we fixed the line fuel pressure dropped down to 40 psi. Which isn't a good sign I'm guessing. All this is for a 2000 suburban 5.3

 

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muddkatt Senior Enthusiast

muddkatt

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40 PSI is too low. Have you changed the fuel filter? If not, make sure you use either an AC Delco, or Wix. Avoid Fram at all cost.

arielleon90 Enthusiast

arielleon90

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40 PSI is too low. Have you changed the fuel filter? If not, make sure you use either an AC Delco, or Wix. Avoid Fram at all cost.

Haven't changed it yet that's on my to do list. Say I change it but problem is still there what next?

 

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muddkatt Senior Enthusiast

muddkatt

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Haven't changed it yet that's on my to do list. Say I change it but problem is still there what next?

 

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One step at a time....

If pressure goes up to above 50 PSI, then that was the cause, if not then at least you have a new, clean fuel filter.

arielleon90 Enthusiast

arielleon90

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One step at a time....

If pressure goes up to above 50 PSI, then that was the cause, if not then at least you have a new, clean fuel filter.

True true thanks

 

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arielleon90 Enthusiast

arielleon90

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So replaced the filter still no change. Next is replacing the fuel injectors.

 

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j-ten-ner Senior Enthusiast

j-ten-ner

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...the previous owner probably wanted to avoid the hassle of taking the gas tank down and replacing the pump...

 

Maybe you just do that.

Preplace the pump.

 

so long

j-ten-ner

arielleon90 Enthusiast

arielleon90

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Maybe you just do that.

Preplace the pump.

 

so long

j-ten-ner

That's going on the to do list as well. Already replaced the fuel filter next is the injectors then the pump all this is on budget so I have to do this one step at a time also as its my daily driver

 

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muddkatt Senior Enthusiast

muddkatt

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Pump first, 40 PSI is too low and only use an AC Delco pump.

arielleon90 Enthusiast

arielleon90

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Question. Will a bad fuel pump cause a misfire on only 2 cylinders (4,5) or will that be due to bad injectors?

 

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