I've got a 2000 Z28 with ported heads, cam, and a FAST intake on the dyno. Deatschwerks 42# flowmatched injectors, 4L60 with 2800 stall. It's misfiring on cylinders 7 and 8. I can feel it plainly while it's running. Misfire detection is disabled at idle and mid range, not that it matters since its truly misfiring. So far, I have done the following:
I did a crank relearn. minimal improvement, virtually no change.
I've swapped the coils from cylinders 7 & 8 to cylinders 1 & 2. no change.
I've swapped injectors from cylinders 7 & 8 to cylinders 1 & 2. no change.
I've removed plug wires and verified they click twice on the coil and positively click on the plug. no change
Installed fresh NGK TR6 spark plugs, no change.
Any ideas what else could be causing this condition?