2010 gmc sierra 4wd 5.3l LC9. Afm/dod engine. Lifter stuck on cylinder 4 replaced all lifters back to factory. New head gaskets intake gaskets plugs wires oil change new coolant. Now sets a random misfire code. Scanner shows 1,4,6 misfiring. Swapped all ignition components with other cylinders. misfire didn’t move. Ran with valve covers off watching the valves and they all open and close. Performed Crankshaft relearn. Still misfires. Any help is appreciated. Thanks

 

did you take a look at the camshaft before replacing the lifters?

 

Yes. It looked good and so did the roller on the lifter.

 

Any update?

 

Right now I am down to the vlom being the culprit. I removed it and bench tested oil circuits and they are leaking past the gaskets into the channel that unlocks the lifters. So now I am waiting for the new one to come in.

 

Ok, thanks.

 

installed new vlom and all is good. Thanks!