My LT1 problem is where I would be in 4th gear (A4) and give it some gas the motor would ping and backfire at around 2000 rpm. It would Idle fine and would get up and go in the higher rpm range but as soon as I get near the 2k mark that where my problem is.

I replace "all" sensors, replace the plugs wires and spark plugs, opti is not that old, coil pack is MSD. These parts dont even have 5k on them yet. The gas is new. Tested the injectors and they passed.

My car ran fine last summer and I stored it during the winter but I started it up twice a month with no problem.

Open loop it runs fine but when it hits Closed loop that where the problems begins.

Any ideas? I'm leaning towards valvetrain issuses....