hey i just bought an 88 gta with tpi 350 bone stock.the guy hollowed the cat i guess.but since ive been driving it hard the car sometimes will only be able to idle.and it wont rev higher than that.other times it cannot go past 3000,or 4000 rpms.its always after i get on it upto like 6 grand or so.is there maybe a piece of the cat stuck in the exhaust sideways or something?