My 2002 yamaha r6 seems to run crappy no matter what i done to it, not
 

sure why. Here's what i did so far: I changed the spark plugs, changed the fuel filter, i cleaned the cars out, then after so many recomendations, completely took them out and have them rejetted. I used so many diffferent fuel additives to help it out, nothing still. The engine sounds good, everyone who listens to it thinks it sounds like it should. When i first got the bike, it ran strong, throttle responce was great and it would pick right up but after a while, it just got weird. When you pull on the throttle, the bike makes a blob blob sound and eventually picks up when it wants to, but response varies though. Sometimes it's real slow, other times it really goes. I just changed the batter and got a new one, still not the solution. They say since i had everything done, i may have a sticky valve, i may try to look into that. Can the fact that my throttle cable has too much play in it cause this issue? Can the fact that i use 87 gas in there sometimes have caused this issue overtime(i mostly use 93). Help!!!!!!

tighten cable change fuel check exhaust for blockedge.Take it back to where it was serviced last and say fix it for free.