93 Protege LX with a 1.8 DOHC and a 5 speed 180,000 miles

It was a free car that my girlfriend is driving until we're done with the restoration of her 72 plymouth. There are no codes popping up, it dosen't blow any smoke, no leaks, it's clean, runs great on flat roads. It needs a new muffler and the cat. has been hollowed out (atleast thats what the old owner told me) I tapped on it and it sure sounds empty.

It's totaly guttless going up hills, overheats when going up a hill, and wont go over 30mph up a hill. Would a new muffler and cat. fix the problem?

 

I would not see how a new muffler or cat would cause this problem unless there is a restriction in the exhaust. Have you checked compression? Spec is 182 psi on that car. I would also check that the timing is correct and that the fuel filter is not restricted. Timing is 10 deg BTDC with the TEN and GRN jumpered on the underhood "DIAGNOSTIC" box.