Help A Chick Out!!!

[Evil torquetress]

I have a 1995 ford mustang gt which has the 5.0l 302. Recently I have been having some problems.....My car feels like its stumbling and just kinda tremles when I give it gas. My smog pumps needs to be replaced it's making noise. I was wondering if that has anything to do with it??? Also when I'm at a stop and floor it it acts like it hesitates and sometimes will back fire. I had my cats taken off so my engine light is constanly on. Well when these problems occur the light goes off. Also when I floor it or take off fast it makes a clicking sound like click click click and stops when I let off. Overall It's running really rough. I was thinking it might be a problem with the fuel system. But I don't know, I was trying to see if anyone had an idea or had any similar problems with their mustang.