I got a 96 zj. 5.2 the jeep runs great and shifts good but when driving even with foot to the floor it won't go past 3000 rpm but if I'm in park or neutral it will rev past that. Any ideas? I'm not throwing any codes my catalytic converter is rattling but wouldn't it make it not go pass 3k rpm even in park? Please help it's driving me crazy

 

It could be the converter, but you should check the fuel pressure and volume first.