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Tahoe & SuburbanThe power, space, and brutal towing ability make the Tahoe and its longer sibling, the Suburban, arguably the best full size SUV's on the market today.
My 2007 Chevy Tahoe 5.3L has check engine light on. Pulled codes and getting P0304 (cylinder 4 misfire). Swapped coils from cylinder 2 to cylinder 4. Swapped wires from cylinder 4 to cylinder 2. both of those produced no changes. Still misfiring on 4. I also did a compression test and am posting the results below. Below is some data that I pulled from the OBD port also. Any ideas? My thought is to check the injector for blockage -any thoughts? from the data collected it appears to be misfiring on more than just cylinder 4 but not throwing codes for the other cylinders. Should I replace the spark plugs they have been in there for a while. current spark plugs have been in there for 30,000 miles. would appreciate some help. just some background: back in 2017 had both cylinder heads rebuilt as I was getting misfiring on cylinder 3 and mechanic tested compression and determined some exhaust valves were leaking/burnt. It ran fine since then until recently.
back of engine
8- 195 psi 7- 195 psi (COMPRESSION TEST RESULTS)
6- 200 psi 5- 195 psi
4- 215 psi 3- 190 psi
2- 195 psi 1- 180 psi
front of engine
actually cylinder 4 was not misfiring-it had a while back but not recently. I removed both banks of injectors and cleaned them with electronic parts cleaner while applying 12volts to the injectors. . cylinder 7 was the one misfiring. and after swapping injectors in other cylinder locations, and placing the injectors back on engine it continued misfiring. I swapped the spark plug form cylinder 7 with cylinder 1 and cylinder 1 began misfiring where it had not before. I"ll be replacing all plugs. FYI
actually cylinder 4 was not misfiring-it had a while back but not recently. I removed both banks of injectors and cleaned them with electronic parts cleaner while applying 12volts to the injectors. . cylinder 7 was the one misfiring. and after swapping injectors in other cylinder locations, and placing the injectors back on engine it continued misfiring. I swapped the spark plug form cylinder 7 with cylinder 1 and cylinder 1 began misfiring where it had not before. I"ll be replacing all plugs. FYI
April 2nd, 2020, 11:10 PM
Misfire code Help
