1995 Dodge Intrepid

I Am Looking At A 1995 Intrepid. It Runs Really Well Except For A Noise That Happens When I Put My Foot On The Accelerator. It Is Some Kind Of A Vibrating Noise. It Comes From Under The Car Somewhere Between The 2 Front Seats. Any Ideas? It Doesn't Happen All The Time. They Only Want 2100 So If It Is A Cheap And Easy Fix, I Want To Buy It. Could It Be The Cad. Converter? Thanks

it could be a loose heat shield, it could also be a weak or broken motor mount, 1st gear in the transmission could also be damaged. Its hard to diagnose without actually hearing it.