my auto will lose power when I start to climb an incline what could this be ? on 1999 Honda Civic

I put a new catalytic converter in also changed the TPI. Also a new timing belt. When I drive on a flat it seems ok, but when I put the ac on the motor bogs down. I put a new radiator in also. It gets worse as the engine warms up, but it dosnt overheat.

Asked by for the 1999 Honda Civic