Prostar 205 engine surge issue
I posted last year about our 96 PS205 having issues with surging. The boat is up north and is not used much. We had codes for TPS sensor and that has been replaced. The boat now does not throw any codes. Last year the boat would run perfect up to 3200 rpm and then surge. We could pull the kids skiing and tubing but not adults who wanted to ski faster than 30. Now, the boat will rev up to full throttle, but will cough for a second before it settles down (almost like turning engine switch off/on). Pulling a skier, the boat will cough every 10-15 seconds in an irregular pattern. The fuel pump inlet is clean, and I replaced the fuel filter today. I am wondering about a fuel line leak or sucking air somewhere (I will check the intake manifold tomorrow). The shut-off valve on the top of the tank does not feel good opening or closing and I wonder if it should be removed/cleaned/replaced?
Also, coming off plane, the engine does not immediately go to idle speeds. It wants to rev at 1500-2000 before settling down to idle in 15 seconds. What else should I check?