power ram 50 won't run over 50 mph

[cotakion]

power ram 50 does not run more than 50 mph it has no power and on climbs it goes up slowly and the engine does not rev it is 4x4 2.6 will the transmission be? I changed to a 2.0 engine and it did the same thing and I changed the carburetor.

 

[Robert Anderson]

check to see if the cat is plugged