Not likely coils, When they fail you'd never get 3600 rpm. I wouldn't think governor issue with the rpm numbers you posted.
I just re-read your first post, @2400 hrs you may want to check into having a leak-down test performed. Worn rings/cylinders will defiantly cause lack of power.......
Originally Posted by piston slapper
You never learn anything until you admit you don't know it all...
"Why go out preserved when you can go out beat up, worn out, sliding in sideways screaming, Holy Sh!t What A Ride" !!!