Buick lesabre revving while driving takes a while to accelerate?

My girlfriends 90s buick lesabre does this thing often when you push on the gas instead of making it go faster it just starts revving and it takes it a little while before it starts to accelerate. What could this be?|||Trans is going out on you.|||Next time you take it in, get the gas filter change, very cheap and TRUST me the most over looked service on a car.|||Sounds like the transmission is slipping.|||There can be several different causes, transmissions and their sensors and vacuum lines can be complicated. There is something you can check and that is the level of the transmission fluid. Note the color, smell, clarity and of course the level against the dip stick. If your not sure what those things can indicate you can ask a mechanic or auto parts store for an interpretation. Hope this helps you.|||Yep...tranny.