My Car WILL Reverse, But Will Not Go Forward When I Put It In DRIVE. It Will Creep Forward As Long As Gravity Is Not Against It, Thus It Feels Like Neutral Even During "DRIVE". What's The Problem?

1999 eclipse spyder, drove home on highway with it 70 miles, did 4 stops where car was turned off and back on and continued to drive, and right as I get home the car rests on the bottom of a kinda steep but not ludicrous driveway then when I go to push gas it just revs like its in neutral but it moves in reverse, I figure it can't be the transmission itself because reverse would not work at all if I can reverse up said driveway.. But I don't know what it could be if not that.

1991 Hyundai Excel runs great except for it doesn't really go very fast when you step on the accelerator.  The engine runs great! But it acts like it doesn't want to drive forward or reverse. It does go, but not like it should. It is very slow even if you floor the gas pedal.
Help!

Check the transmission fluid but it sounds like your transmission is busted,

Same exact thing happen to my car yesterday. So it is the transmission?

If the transmission has enough fluid in it then it could be any number of things internally which will probably mean removal for diagnosing. Good luck!

Looks to me like a transmission problem. Probably need a Tranny FLush or Diagnostics. 150-200$