Looks like my car does not have enough power

Hi everybody. I have a 1995 Chevrolet Corsica 2.2L. Looks like my car does not have enough power.The angine is fine, but when I bought it 3 months ago it was kind of faster. One time it got overheated, and after that it runs slower. My friend sad that the catalytic converter needs to be changed, or even replaced with a piece of a tube. He also sad that the converter might be clogged up and that's why the car dont have a lot of power.

thanks for replies

that might be a factor...