We currently have a problem with our 2388. It's like it has no power, like it lost 15-20hp. We are running 0.5-1.0 mph slower than we used to. We have replaced the water seperator filter, fuel filter, and the air filter. At the high idle it makes a surging sort of sound.At all other ranges it still seems to sound the same. Again the power just isnt there like it was a week ago.