Domss2000

i had just left my house and down the street the car turned off. then i check my gauge and there was no fuel pressure.But when i towed it home after a while it had pressure again. My question is when i turn it on its at 40 but will drop to 38 or 37 sometimes and then i give it a little gas to idel and hold it there it will drop to 35 psi is that right? i thought was not suppose to drop. it my 96 trans am

Injuneer

To check the fuel pressure:

With engine idling, remove the vacuum compensation line from the fuel pressure regulator. Pressure should be in the range of 41-47psi. Best pressure would be 43.5psi.

Reattach the vacuum line to the FPR. Pressure should drop proportional to intake manifold vacuum. Up to an 8psi drop is normal with a stock cam. Less drop with a more radical cam.

At WOT/max engine RPM pressure should be close to the same value you got with the vacuum line disconnected.

The pressure will vary with throttle position, and whether it is opening (pressure increases) or closing (pressure decreases).

Have you checked for codes? Loss of the low res pulse from the Opti will shut the fuel system down.

LaredoZ28

it sounds like u have a bad fuel pump, plugged fuel filter, or a bad fuel pressure regulator. I'd suggest hanging the fuel filter first since its cheaper.

Domss2000

the fuel filter is new regulator is good just checked it. might be fuel pump cause when i open the throttle the psi drops and doesnt stay in the 40 to 45 range and holding the throttle half way the psi also drops to 35 psi or 34 and when it does that the car feels like it wants to turn off

LaredoZ28

Yes it would b ur fuel pump then.

Domss2000

yea ill check the pump right now thanks for helping me out you all