I got to see yesturday how much psi my fuel pump is giving the car, it was at 34psi i believe this is low. at 3500rpm it went to 44 psi. I was told it's out of spec by 4 psi, should i get a fuel pressure regulator?

 

What year is your car?

If its a 94+ using an adjustable AFPR will do nothing because the PCM recompensates.

Swap in a new factory FPR.

If the psi drops when u accelerate you might need a new pump.

 

it's a 95 z28.

The guy who tested my car said i just need an AFPR.

 

Did he disconnect the vacuum line to the FPR before he measured the pressure?

If not, results look a shade low, but acceptable. 41-46psi at idle with the vacuum line off. When you reconnect the vacuum line at idle, it will pull the fuel pressure down, in proportion to intake manifold vacuum so 33-38psi might be seen. At WOT should return to the "no vacuum" reading and stay there all the way to red line.

I suspect he didn't take the vacuum line off.

 

The idle reading was 34 psi and with the vacuum hose off it was 44 psi

 

Those are the correct values. Why did he think the fuel pressure was too low? You need to wind it out to near redline, and check to be sure the fuel pressure holds at 44psi all the way at WOT.

 

Thanks, the guy is probably trying to make money off me

 

your fuel pressure sounds fine. Tech manual says 41-47 psi WOT and you are in the middle. Mine is the same, I was hoping it was the answer to my misfire problem I posted a little while ago. Good luck. What is your car doing that you are checking your psi anyways?

 

I cheked it cause i thought the fuel pump might be slow. when i downshift the car leave it there for a couple seconds then hit the gas the car just flys! but when i downshift and hit the gas right away it doesn't feel like it goes as fast as when i wait. So i thought it might be the fuel pressure.