To update, the fuel pressure with the system primed but not running is 52
psi, running is 42 psi, running with the regulator vaccuum line disconnected
is back up to 52 psi. I replaced the fuel filter since I had no idea how
old it was, no change in pressure readings. I also cleaned the EGR valve
while the plastic cover was off just for the hell of it, and replaced the
oil pressure sending unit hoping that it's related to my occasional 'check
oil' light. More likely to be the oil level sensor but the parts store was
useless on that one and the pressure sensor was cheap.
All of this resulted in throwing the same two codes on the next trip, P0300
and P0442. What's left for the misfire, injectors or the crank position
sensor? If it was an injector or two, wouldn't it throw a code for that
cylinder rather than a 'random misfire' code? Aside from when that 'check
oil' light occasionally pops up, there really are no drivability problems.
It feels good and strong although it does run fairly hot.