Stumbling Issues

I know this is being discussed in a couple other posts but, mine's not a newer XJ it's a '92 4.0. So, I hope not to get flamed on this. All my sensors meter out good and no CEL. no codes but 12, 55.Today I checked the plugs and replaced cap&wires.

Checked fuel presure and getting mixed readings, Once it was 24psi and slowly dropped to 0 after shut down.
Checked it again 1/2 hr later and I get 30psi, holding for a few after shut down.
Pinching return line while running didn't cause an increase in presure.
About to go check it again in a minute.
When I give it gas the presure drops RMP depending.
Just did a 3rd check on the presure. 31psi with the key on 26psi with engine running. Doesn't make a differance if the vacum line on the regulator is hooked up or not. Still dropping psi when it's given gas. Had a psi increas to 40psi afterr shut down for 5min., start it back up, drops to 25psi. Thanks for any help, Chris

Fuel Pressure Spec

Fuel pressure should be 31 lb running, 39 with the vacuum line to the regulator disconnected.

Have you replaced the fuel filter (or is it in the tank for a '92?).

The 92 with a 4.0 has a fuel filter along the frame rail over the rear wheel on the driver's side.

Sounds to me like either your fuel pump and/or filter is on it's way out.....

Problem fixed. Fuel pump was the only issue. I had replaced the filter a few days prior. Thanks for the help. Chris