I have a 1998 acura CL 3.0, I am experiencing a problem, when I press gas the odometer gauge goes up but car don't move.

I had same issue about 4 months ago and was told that "MAP SENSOR" was bad, replaced it (put used one in), that seemed to fix the problem, but I got the same issue again.

Any commensts / suggestions?
What exactally is "MAP SENSOR" and what is it used for, any help will be greatly appreciated.