F150,2015 yamaha skipping

[G Hierholzer]

I have a 22' shrimp trawler powered by F150 yamaha.runs great .Under a work load thats consistently around 2500 rpm's it develops a mild skip after several hours of towing.I have been through the fuel system looking for air leaks ,water filtration system is good,had the injectors cleaned manually but not on a machine.After the injector job it ran better but the skip is getting worse only under a load and after some time.When I take up my gear and run back to the landing ( 25 knotts) not a skip.
What should I be aware of before taking her in for repair.

Thanks for advice.