Chugging going uphill and smell of gas near the tank

Check the fuel pressure.

tune-up, dirty gas, dirty air filter...when last completed?

sounds like fuel filter or pump

Not to scare or offend you but it could be many many things. It does help that the check engine light is on, though.
If you can go to a place like Autozone, where they check your check engine light for free, and post what the code was, I can give you a place to start.
I do not mind helping you further with a proper diagnosis procedure either, if you can share your vehicle information.

Sounds like a MAF(Mass air flow sensor, you can start by pulling it out, it's inside the intake box on this car. You can clean it with a high percentage isopropl alcohal or MAF cleaner, this sounds to be the problem, if it is really bad, you can unplug it temporarily, it will not have as much power but it will run better. If cleaning it doesn't fix it, then you will need to replace it, ensure not to touch the sensor itself at all.

the convertor is the problem.will cause decreased engine power, another sign is bucking and jerking upon accelerating. the car will lose power when going up a hill. if engine runs hotter then usual and coolant is up to par, may be a bad converter.

I would start with the filter.

the first thing i would do is put some STP gas treatment with fuel injector cleaner in it also make sure you have at less a half tank of gas in it and drive it on a back road where you can get up to 55mph Merry Christmas and Happy New Year as always wish you the best of luck Michigan Man

Could also be a faulty mass air flow meter, or throttle position sensor. It's hard to tell, you need to take it to a shop to be properly diagnosed.