Just put a fully rebuilt 5.7 engine back in and adjusted the CAM Retard Offset to +1 degree using Torque app. No other codes except P0300. Have limited data access to ECU at moment, but some data includes, at idle and warm engine: Intake Manifold Pressure at 36 kPa (10.6 in Hg) MAF at 7.22g/s dont have fuel pressure dont have any Trim Data Scanner has clearly indicated misfires on cyl 5 and 7, the others cylinders are solid. I've only swapped plugs (41-993) and cap/rotor so far, no change. I also sprayed carb cleaner...no response Tomorrow I was planning on swapping some plug wires. Any other suggestions to help debug this?