if its an aftermarket clutch then you prolly have stiffer springs in it. if its slipping you may as well get a new clutch kit. buy a new clutch and install 3 stock and 3 stiif springs and it wont be too bad. personally i want all 6 stiff springs since im pushin alot more power than stock. its personal preference. also, like fixitrod sais you may need a new cable. they get shit in them sometimes and that will resist pull as well.