Intermittent Shutdowns - I think its fuel related but looking for advice

[ColeHarmening]

Hey all,

Welp after putting about 400 hours on my A4 this summer going fishing offshore with my A4 running great the whole season I am now having shutdown issues.

I checked my ignition and wiring connections, re ground my E- fuel pump hoping that was the issues. Test run it in my slip for 2 hours, it runs fine. Go out daysailing with people and it shuts down while we are headed back to the harbor. I replaced my filters and re did my fuel line, tested the engine on short runs and in the slip for a few hours. It ran great, then go out day sailing again with friends and it randomly shuts down and it takes some starting and restarting finagling before it runs long enough to get us back into the slip. Now I am running it in my slip and trying to get it to shutdown so I can go through my shutdown spark and fuel tests. But its running great in the slip for about an hour and I can't get it to repeat the issue. My hypothesis is that my fuel tank has crud in it and every once in a while (seems like whenever I am out sailing with friends) the fuel pickup is grabbing a piece of crud and clogging the line so the engine starves and shuts off suddenly. Our last outing the way I was able to finagle the boat back into the slip was to unplug the E-fuel pump + wire then plug it back in. This seemed to keep the engine running for a few minutes. My thought to fix this issue is either to do a diy fuel tank polishing or hire a company to come do it. Wondering is there any other issues you guys recommend me checking out before spending the money on a fuel tank polishing service?

I leave on a 6 month cruise to Mexico in a few months so I am very keen on getting this problem sorted and return to an engine that I trust. (Ive cruised about 1,500 hours and 3,000 NM on my A4 in the past two years)

A few things to note: This spring before my summer fishing outings, I re did my E-ignition with the indigo kit, new distributer cap, new spark plugs and wires, new OPSS etc. With this in mind I am leaning towards this being a fuel related issue rather than spark problem.