What I would recommend you do is drop by a chain type auto parts house (Checkers, AutoZone, etc) and have them scan the car for codes. They will do this for you free of charge.
Just clarify something. From your original post it was made to sound like the car would not move (as in one inch) and your last post gives the impression the car will move but the acceleration is not what it should be.
If it’s the latter then forget the transmission angle of this.
There are a number of things that can cause an idle problem or an off-idle problem.
(Vacuum leak, intake tract leak, MAF sensor, IAC valve, TPS, etc, etc)
Hopefully, a scan may produce something to work with and I never thought it was bad gas to begin with.