fuel

May be incorrect plugs or wrong plug gaps and do a scan and let me know if there are any codes to deal with, start here.

The cats are cut off just seen that so ses is on but before I changed everything it still got 19.8 with the old stuff

and now it kinda shakes but eveything was fine until i changed it all

leads on correct way? did you re check what i said.

everything is on right and i put autolite what was called for the car and yes the engine light comes on/off because the cats are cut off it but it ran completely fine before i done a tune up and now it runs like crap now

I will be something to do with what you have done with the tune, i would carefully re check all that you have done first.

The plugs are almost stock gapped at .56 like it says and it has new wireset on it and new airfiltef so isn't anything I can recheck I've done it twice so far and it keeps going down hill in gas and performance

you got any codes, you can have codes with out a check light being on as well.

well the engine light is on/off sometimes but can't get anywhere to read it and don't know where to put the key to cross over to read the codes

Autozone and Pep Boys, as well as a number of auto parts stores will scan for codes for free. The diagnostic connector is located on the left bulkhead on the wiper cover. Jumper this connector and turn the ignition to the "Run' position. Count the flashes of the 'Check Engine' light. Count the flashes and let us know what you get.