another 4.3 running like crap
#1
another 4.3 running like crap
i just picked up a 99 zr2 blazer, has a miss when i bought it... really bad, was sitting for a couple months, the guy didnt have money to put into it so i picked t up fairly cheap... has 170xxx miles, got it home, did normal stuff, cap, rotor, coil, plugs, wires, fuel filter.. fixed acouple vacuum hoses. ran better but not perfect... ran a compression test all cyl. between 115 -125 psi.. ran a fuel pressure test, just key on goes up to 62psi.. at idle bounces between 52-56 psi.. i replaced the spider with new updated version... runs better but still stumbles and misses... mostly under medium throttle between 1500-2100rpm and at idle... not sure what else to do ... i removed the cat. and gutted it.. had code p0300 for miss fire, cleared it out light hasnt been back on... had a code p0452 evap pressure sensor signal low/ short... cleared hasnt come back.. also when i take fuel tank cap off it releaves pressure.. none of my other s10s have done this.. any help would be great!!! thanks for your time...
#7
I took a brand new cap out of the box installed it on mine and chased a cylinder #1 missfire for 3 weeks before I listened to this forum and brought a delco cap, The forum was right! cap was the issue, and visually the other cap looked perfect