[cantstopgrandma]

Sounds like you got some spark plug wires crossed...but i'm no mechanic. Its easy enough to do, and will cause it to run VERY rough.

 

[cantstopgrandma]

Usually when a cat gets plugged, the engine runs good pretty good until you put a load on it (trying to accelerate). I'm not saying that it couldn't be your problem, but the last couple i've encountered run good until you put a load on them. I am especially doubtful now that you say it got worse after the tune up.