Fuel Jumping, lost power, Back firing, only has 20 psi fuel pressure

[Case4]

I have a 92 G.T, and recently it has lost power, it's got a aftermarket fuel pressure regulator on it and it won't go past 20 psi, and it's started jumping and back firing, I need help, any advice would be appreciated.

 

[JMG9350]

Is the regulator adjustable?

 

[Mcmahst]

Welcome to Stangnet. So, tell us more about the circumstances. Did you have greater than 20 psi in the past? If so, what was it at idle? Did the running problems result with the fuel pressure change? If so, it could be a few things. One, it could be a failed regulator. If it’s not adjustable, you need to verify engine vacuum, since that’s what makes it work. If all of that checks out, it could be something restricting the fuel flow; filter, something in the tank, etc.

But first, we need to know the FPR type. Remember, these engines are know vacuum leakers, since there are so many places you can have one. So, make sure it’s not a bad vacuum leak before you spend money on parts. Good luck.

 

[mikestang63]

could be a number of things

clogged fuel filter
clogged fuel line
regulator gone bad
bad fuel pressure gauge

I would check your plugs to see if they are showing signs of running lean

You can start by disconnecting the fuel pressure gauge from the regulator and hook up an external other gauge to confirm the FP. My guess is the FP regulator diaphragm is bad or a clogged fuel filter.

 

[Case4]

Is the regulator adjustable?

Yes

 

[Case4]

Welcome to Stangnet. So, tell us more about the circumstances. Did you have greater than 20 psi in the past? If so, what was it at idle? Did the running problems result with the fuel pressure change? If so, it could be a few things. One, it could be a failed regulator. If it’s not adjustable, you need to verify engine vacuum, since that’s what makes it work. If all of that checks out, it could be something restricting the fuel flow; filter, something in the tank, etc.

But first, we need to know the FPR type. Remember, these engines are know vacuum leakers, since there are so many places you can have one. So, make sure it’s not a bad vacuum leak before you spend money on parts. Good luck.

Yes in the past I run 45 psi, whoever had the car before me cut and removed alot of stuff that I'm not sure of, there's a lot of plugs not hooked up, but I can't find where they go.

 

[Mstng93SSP]

Low fuel pressure can also be the S hose cracked on the fuel pump.

 

[Mcmahst]

Post pictures of the unknown destination plugs, both close up and a bit away for context, and some smart person on this site will help. Did you ever verify the engine vacuum at idle and 3500rpm? Having stuff cut up and removed is bad bueno.