Strong smell of gasoline after doing tune up

I have been driving it for about 6-7 years. No major problems, except for needing the alternator and a new battery and I smell gas when I checked my oil that's from a leaky fuel injector, but I thought I felt some other minor things that prompted me to do a tune up. So I decided to do a tune up. New spark plugs and wires, did oil change plus new oil filter, and I also did transmission oil and a new filter. So after tune up I started it and it wouldn't run properly was misfiring, and the malfunctioning light (check engine light) came on. So I decided to check the spark plugs and wires so cleaned spark plugs back to new, also double checked the gaping but decided to use old wires do to them still looking like new. I disconnected the ground wire to reset the check engine light.
I figured if there was anything major it would through the check engine light again but it started right up and runs great, but there is an over powering smell of gasoline. So I turned it off and now here we are. What could be causing this so I can fix it and drive it again? I don't want to destroy the catalyst or catalytic converter or anything else. Could you please help?