I'm slowly working through all of the issues with the 93 C4 project car I purchased a couple months ago. When I check pin "B" during cranking I don't get the 1-4vac as indicated in the FSM - I get around 0.2 - 0.7vac. All other checks on pins A, C, D check out and all pins on the ICM check out with the new ICM (original was dead and failed the FSM procedure).

The car will start and idles with a misfire. It revs fine at idle but once you load the engine with reverse or drive it runs much worse. When taking off from a dead stop if you go easy on the throttle it will stumble so hard it nearly stalls and begins backfiring. Harder acceleration will allow it to get up and move. Once it gets moving it will drive fine until you stop again. Doesn't seem to matter if engine is cold or hot. I have monitored the fuel trims and it does run a little rich, but given the backfiring and miss I believe if these are corrected the fuel trims will level out also. O2 sensors react as you would expect after warming up.

Have already replaced plugs and wires they were old and looked original to the vehicle, replaced ignition coil, fuel injectors and fuel filter due to not knowing the age or condition of anything figuring it should be done anyway as "tune up" items.

Would the lower than normal voltage on cranking be enough to condemn the opti and go ahead and replace?

Edited to mention: I don't have any codes stored.