i have a 98 gtx limited and when i start up its fine and idles fine but when i try to get up on plane it revs to about 8k rpms and doesnt really move. i hear a loud whistle/rattle in the back and it creeps until up on plane then kinda goes. i feel like i have absolutely no power. is there something wrong with the impeller? i pulled it out of water and looked up in there and coulnd't see anything except the little black cap sliding up the shaft. its the only thing that looked loose. could somthing be stuck in between the impeller blade and the pump that i cant see??? help!