Catalytic converter causing car to not run right

I went to a mechanic a month before for regular oil change up. What he did was shocking for me he said my catalytic converter is chocked he poured some acid in without disassembling catalytic converter and then rev car up to throw acid out of exhaust. As a result car feels heavy to me. Then I went to another mechanic he then cleaned it by removing catalytic converter and then again putting it, but I felt no change. I finally decided to do a compression test (dry one) and it was normal. Car is not is same in power this is what I feel: feels something is wrong but compression test is fine. Please suggest something.