P0300 ALL NORMAL CAUSES REPLACED AND CHECKED LOST.

Question

2008 2500HD 6.0 gas. p0300 random misfire new plugs wires injectors went to dealer told cylinder 2 and 4 misfire under load. Did compression and cylinder leakdown all within specs. Proper fuel pressure coil packs tested ok cats not clogged no vaccum leaks lost and broke now. Any thoughts

Answer 1

If this engine has the AFM (active fuel management) these have lifter that unlocks , and it would be accompanied by a ticking noise. this would be one of the probable cause that you may have, there is another this deal with carbon build up, In either case run a fuel injector cleaner , Having cylinder 2 and 4 right away the though are head gasket.