Postby mosilvia » Wed Oct 05, 2022 3:49 pm
I haven't done a fuel pressure test, but first of all, after replacing the fuel filter on the 1992 300 ZX, the lamp was still on, so I installed an adjustable fuel pressure regulator and pressure gauge. I adjusted it to 43 psi at key on 34 psi at idle. With the key on, the pressure suddenly dropped so I checked the fuel pump and the hose clamp was loose. When I closed it, the pressure returned. I turned off the lamp on the obd2 scanner, but it started coming on again, and when I checked, I got p0171 and p0402. The idle is very stable and the engine runs well. What else could be the cause?