To start this off i have had a rough idle for some time now probably going on 20,000 miles or so. But its only rough when in drive, odd thing it seems better when the air is on. Anyways recently i started smelling gas when I would start the car or accelerate. My gas mileage has definetly gone down and it takes a high rpm to accelerate between 2500 and 3000 just to go from 30 to 45. I changed the spark plugs two weeks ago and they are gapped properly as well as wires so that eliminates that part of troubleshooting just need help from there especially with the fuel smell.

 

Try checking for leaks from your gas tank to your injectors. If the issue is fuel it could be a bad fuel pump all the was to leaking O-rings on the injectors. Neon's have no replaceable fuel filters but there is a fuel regulator near the fuel tank.