my 03 lancer es automatic will not change gears smoothly. I think it is due to the ignition system. i changed the spark plugs with oem and used aftermarket plug wires. i ran perfect for a couple of days then went back to running rough. it has been throwing a bad catalytic code off and on for 3 months but i am not sure if that can cause the surging and hesitation between gears. i just wiggled the wires and switched the coils (so i think the coils are ok) and it runs a little better but when i brake and come close to a stop it does some jerking. i can smell gas in the exhast and i think it is not burning it properly but i am not to sure. My car has been acting this way for a couple of months now

does anyone have an idea as to what i should do? should i take it to a mechanic? could it be the fuel injectors? could it be the ignition coil boots?

i hate the way it is running it feels like i have a crap car