Keiterburb
TYF Newbie
Hello, 2012 Suburban 198,000 miles Vin 7 LC9 5.3 completely stock config and parts having P0305 CYLINDER 5 misfire with misfire felt at idle and smooths out under throttle. Recently began also seeing P219A. Under idle and cold temps in Wyoming the traction control will alert and turn off until rpm’s increased.
Began by pulling #5 plug that looked carbon fouled black but dry. Swapped plug, coil , wire with #3 that was burning clean. No change in condition.
Cleaned stock Air Filter, Removed and cleaned throttle body and intake of a little pcv blow by oil. No Change
MAF sensor intake flow side looks a little black but reading on live data. Fuel pressure 43-58psi, Short term fuel bank 1 was -7 to -12 during test drive.ECT sensor was reading appropriate temps.
Removed valve covers and used starter relay to crank and observed all rocker arm moving, all had same 1/32” slop when not compressed.
Removed all plugs and ran compression test most cylinders including #5 were at 150psi +\- 10psi. Failed at this point to perform leak down test as I felt all lifters were doing their thing and I am shadetree mech.
Replaced all 8 plus and wires, removed intake manifold and replaced gaskets with metal Fel-Pro after cleaning. Replaced all 8 fuel injectors with stock GM replacement from rock auto. Throttle body gasket as well.
No fuel leaks and fired right up post install but remained with same misfiring #5 only now my back felt broken as a result . Wiggled injector wiring from top to bottom while running with no change at idle misfire.
I am assuming next test will be cylinder leak down check and will be my first time trying that.
Any help would be greatly appreciated!!
Began by pulling #5 plug that looked carbon fouled black but dry. Swapped plug, coil , wire with #3 that was burning clean. No change in condition.
Cleaned stock Air Filter, Removed and cleaned throttle body and intake of a little pcv blow by oil. No Change
MAF sensor intake flow side looks a little black but reading on live data. Fuel pressure 43-58psi, Short term fuel bank 1 was -7 to -12 during test drive.ECT sensor was reading appropriate temps.
Removed valve covers and used starter relay to crank and observed all rocker arm moving, all had same 1/32” slop when not compressed.
Removed all plugs and ran compression test most cylinders including #5 were at 150psi +\- 10psi. Failed at this point to perform leak down test as I felt all lifters were doing their thing and I am shadetree mech.
Replaced all 8 plus and wires, removed intake manifold and replaced gaskets with metal Fel-Pro after cleaning. Replaced all 8 fuel injectors with stock GM replacement from rock auto. Throttle body gasket as well.
No fuel leaks and fired right up post install but remained with same misfiring #5 only now my back felt broken as a result . Wiggled injector wiring from top to bottom while running with no change at idle misfire.
I am assuming next test will be cylinder leak down check and will be my first time trying that.
Any help would be greatly appreciated!!
