Thanks for reply Tateau18. I'll clean the fuel filters and fuel pump screen next time out and see what happens.
I started troubleshooting by checking the Perfect Pass and had there tech services walk me through a control test and a series of reprogramming. Nothing seemed to make a difference with engine surging, so I disconnected DBW Master Module to send in to PP for software update.
Unfortunately, the throttle surging continued after removal of PP, so it's not going to be that easy of a fix. The Perfect Pass technician sent me this tech bulletin so I might give it a shot before having to haul boat 3 hours away to a MC dealer.