I have a 97 gtx and after completely cleaning the carbs and rave valves the thing just isnt running right. it will take off and at full throttle be about 4800 rpm but only go like 25 mph. once in awhile if i play with throttle i can get it to plane out and run like 50 mph. once i get it up and going as long as i stay on full throttle it runs great. meaning that if i spin a cookie and the machine comes to a stop if i never let off it will pick up and keep going. but if i let off throttle and try and get back on it stays at like 25 mph again until it eventually picks up again. any ideas? it has me real confused.