boy&hisdogs
I'm Awesome
98 K1500, 5.7/4l60e, 198k miles (It's the truck in my sig)
Three times now over the past year or so my truck has given me P0302 (Misfire #2) at idle and low speed/rpms, like when I'm pulling out of the driveway. The first time it went away on it's own after a few days, before I could figure out what caused it. The second time it lasted a couple weeks and went away a few days after I replaced the plugs and wires (Probably a coincidence?). It's back again and now it also gives P0300 (Random/Multi cylinder misfire) while driving at road speed. It starts strong and has enough power to drive around on flat land but climbing big hills it feels weak.
So far I have done new plugs, wires, cap, rotor and coil, all AC Delco, Seafoam in the oil and vac hose (surprisingly little smoke), and two rounds of Lucas injector cleaner in the gas. No noticeable change. I don't mind throwing cheap and easy parts at it that it probably needs anyway, but now it's time for more serious diagnostics. I'm worried that it might be the injectors/spider, since as far as I know it's never been replaced or even checked. I'm the 2nd owner, I bought it in 2010 @ 62k miles. I did replace the intake manifold gasket soon after buying the truck and replaced the fuel pump around 6-8 years ago with a Bosch one that runs smooth and quiet.
Is there any way to check the injectors without taking the intake off? What about the distributor itself? I've heard of them stripping teeth around this mileage. What else should I check? Fuel pressure and compression seem like the next step, but if those are fine then what?
I don't know if this helps, but I pulled some interesting data with my scanner. Bank 1 O2 sensors read like a bad cat and bank 2 reads clean despite the misfire. This was with the engine warm and cruising down the highway about an hour long drive.
EDIT: Might be worth noting that the misfires came back recently after about a week of the truck sitting without running/driving.
Three times now over the past year or so my truck has given me P0302 (Misfire #2) at idle and low speed/rpms, like when I'm pulling out of the driveway. The first time it went away on it's own after a few days, before I could figure out what caused it. The second time it lasted a couple weeks and went away a few days after I replaced the plugs and wires (Probably a coincidence?). It's back again and now it also gives P0300 (Random/Multi cylinder misfire) while driving at road speed. It starts strong and has enough power to drive around on flat land but climbing big hills it feels weak.
So far I have done new plugs, wires, cap, rotor and coil, all AC Delco, Seafoam in the oil and vac hose (surprisingly little smoke), and two rounds of Lucas injector cleaner in the gas. No noticeable change. I don't mind throwing cheap and easy parts at it that it probably needs anyway, but now it's time for more serious diagnostics. I'm worried that it might be the injectors/spider, since as far as I know it's never been replaced or even checked. I'm the 2nd owner, I bought it in 2010 @ 62k miles. I did replace the intake manifold gasket soon after buying the truck and replaced the fuel pump around 6-8 years ago with a Bosch one that runs smooth and quiet.
Is there any way to check the injectors without taking the intake off? What about the distributor itself? I've heard of them stripping teeth around this mileage. What else should I check? Fuel pressure and compression seem like the next step, but if those are fine then what?
I don't know if this helps, but I pulled some interesting data with my scanner. Bank 1 O2 sensors read like a bad cat and bank 2 reads clean despite the misfire. This was with the engine warm and cruising down the highway about an hour long drive.
EDIT: Might be worth noting that the misfires came back recently after about a week of the truck sitting without running/driving.
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