I just bought a 97 Pontiac GrandAm and I drove it all around today and it seemed to be running fine. Then to test out the strength of the car I was doing about 50mph and floored it til I got to about 70mph and then let off, I made a turn and then came to a stop sign and the car would not go. You can hear it shift into gears but when you push the gas it sounds like it is in neutural and goes no where. I checked the transmission fluid and it was fine, so now I have no idea what's wrong... Any ideas?