I bought a 91 4runner, supposedly a rebuilt 3vze in it (some paperwork to prove) but hasnt run well since rebuild, almost 10 years ago. I have been researching relentlessly about what causes this and the fixes. So far i have replaced all related relays (efi, cor, etc), ive replaced all fuses in engine bay, and checked the fuses in the drivers kick panel, which were all good. I tried a different ecu, checked voltage to ecu and it was good. Ive replaced ignitor, dizzy, wires, checked voltage at coil, checked voltage going to dizzy, etc. Which were all fine. Recently found a thread on here about how the maf could be the issue, i popped mine open and it was fine. I have an extra that i know is good, tried it anyways, and it made no difference. None of which has made the fuel pump prime or run at all when the key is turned. When jumping the fuel pump, the vehicle starts right up, but runs poorly. Once revved up past 2k, the check engine light comes on and gives code 52.

My thoughts are the injectors aren't receiving correct voltage and causing the knock sensor to trip, but I still am at a loss as to why the fuel pump will not run unless jumped.