Very Frustrated, Please help! P0300

:crying: Hey everyone, 2000 Tahoe Limited 5.7L 4dr/2WD. Heres the story, wonderful truck, I have had it since 2006 no major problems until now. I parked it last October due to a braking problem. While I was gone my cousin drove it for a little bit up and down the street until it was almost out of gas. I just got back from Italy last week and she wouldn't start. Jump started it, with a lil help from brake clean got it running. It had a horrible horrible idle, it smoked for a few minutes then tripped P0300 code and it was misfiring thru all RPMs then shut off. It wasnt serviced since summer of 2007 so I drove to Napa, and burnt a hole in my wallet. I just changed the oil, flushed the coolant, flushed the gas tank, new fuel filter. I pulled and replaced the plugs (they were charcoal black) wires, cap, and rotor. The coil checked good. I put new gas in with a bottle of STP and then it wouldn't restarted. I purged the fuel lines and it started right up but I would have to give it some throttle to keep it running or it would shut off. It misfires at low rpms/shuts off at idle/ and has a slight misfire at anything over 2k RPM. I am stumped, Im going to try Idle Control valve and/or Fuel Press. Reg. when I get off work.... Any ideas suggestions, words of wisdom?

I read about something called spider valves or something? Any info on how to remove/clean those????

Welcome to AF. Start by checking fuel pressure, at least 60 psi ( Vortec, I assume), also see if it leaks down quickly after shutdown.

:crying: Hey everyone, 2000 Tahoe Limited 5.7L 4dr/2WD. Heres the story, wonderful truck, I have had it since 2006 no major problems until now. I parked it last October due to a braking problem. While I was gone my cousin drove it for a little bit up and down the street until it was almost out of gas. I just got back from Italy last week and she wouldn't start. Jump started it, with a lil help from brake clean got it running. It had a horrible horrible idle, it smoked for a few minutes then tripped P0300 code and it was misfiring thru all RPMs then shut off. It wasnt serviced since summer of 2007 so I drove to Napa, and burnt a hole in my wallet. I just changed the oil, flushed the coolant, flushed the gas tank, new fuel filter. I pulled and replaced the plugs (they were charcoal black) wires, cap, and rotor. The coil checked good. I put new gas in with a bottle of STP and then it wouldn't restarted. I purged the fuel lines and it started right up but I would have to give it some throttle to keep it running or it would shut off. It misfires at low rpms/shuts off at idle/ and has a slight misfire at anything over 2k RPM. I am stumped, Im going to try Idle Control valve and/or Fuel Press. Reg. when I get off work.... Any ideas suggestions, words of wisdom?

I read about something called spider valves or something? Any info on how to remove/clean those????


after the fuel pressures check...check injectors for leak down most likely ,,,dirty if you did not use stabilizer in the gas this would cause this...also running fuel pump with no fuel is a good way to quickly destroy pump....plug wires will need resistance check as you have misfire...use dielectric grease in the plug boots


whenever storing a vehicle it is best to not run vehicle at all...remove battery and put 1 oz of marvel mystery oil in each cylinder and seal the air cleaner so that moisture can not get into engine..use gas stabilizer at 2x strength and fill gas tank to 7/8 .....run then stabilizer into the engine before complete shutdown....spray engine store into the intake is also helpful...lift vehicle so tires are off the ground...