you need to lift the car up and check the bushings, check for the play in the half driveshafts...

Also, while car is on the ground, engine running, put the car in gear, hold the brakes, and try to rev the engine (not like you are going to race! a little bit) - if the engine is acting like it is ready to jump out the engine bay, you might have engine mount issues. You might need two people to do this one.