1996 gtx runs fine sometime

[1955rex]

My 1996 gtx has me baffled. I have replaced the following; mpem moduel, rev moduel, coils, voltage reg,and the carbs rebuilt,When the ski runs it actually runs fine ,but sometime(and this is getting worce)the ski will accelerate up to 6000 rpm then slow to an idle.If you try to pullout again the will accelerate only to 4000 rpm but if you unplug the dess lanyard (key?) the ski will accelerate to 6000 again. This problem use to be not bad as it is now???????????

 

[sunbaby69]

sounds like a fuel issue, check fuel lines and filters. if nothin wrong there then I suggest rebuild carbs. waht is compression? how old are spark plugs?