Silverado 2012 6.2 ( L9H ) Misfire at idle

[eisaalali]

Hello guys

Having an misfire issue at idle on cylinder 7 only, Silverado 2012 6.2L ( L9H ) the truck has TVS1900 supercharger and full bolt-ons.

what we did trying to get rid of this issue :

1- spark plug has been change
2- spark plug wire has been change
3- coil has been change
4- injector has been swap with other cylinders injectors that has no misfire
5- injector harness has been checked
6- both heads has been checked
7- pistons and rings and connecting rods are new

this issue occurs after water leaked form the supercharger in the the cylinders
the misfire only shows at idle and makes the Truck idle rough, can a bad O2 sensor or maf cause this issue ?

Please take a look at the log and advise

thanks

[blindsquirrel]

Swapping a known-good is a good idea, but more important thing to know is: is the #7 injector firing? Constant IGN on one pin, switched ground while running on the other?

Injector balance test (pressure drop)? You will need a different (real) scan tool and pressure gauge to do that test.

You can't really diagnose anything about the O2 sensors or trims as long as it's misfiring. Misfire will look like a lean condition, since the oxygen ingested by the cylinder gets sent down the pipes without being burned.

MAF can't affect only one cylinder.

[BigTuner]

Have you done a compression test? I know you said you checked the heads but if the bottom end is fresh and you had hydro lock and now have a misfire I would think it is something valvetrain related. Maybe a bent or tuliped valve not closing fully?