I wouldn't worry too much about spark advance around idle. Some of the spark stabilization has the advance all over the place during idle. You could do throttle sweeps Key On, engine off to see if the voltage sweeps smoothly.

TPS, IAC RPM, MAP and also look at AFR if you can.

Thanks Kindly for the reply. I was only going to do spark as I'm hanging onto the coat tails of another fella with a 502 MPI that had the same issue as I. He finally solved it after replacing the ignition coil. He found the coil output to be weak and the MPI was attempting to make up for said weak coil. In doing so he had the same throttle surge I'm experiencing. I have since switched over the "good engine" ignition coil to the "bad engine" and just waiting on a fair weather day to see if it corrects the "bad engine" surge issue and/or switches the issue to the "good engine."