motor mount going?

I have a 96 Continental w/91.5k miles. There is a slight vibration while under acceleration that I can feel predominantly through the accelerator (but I can also see the passenger front seat wiggling, too). The other day, I put the hood up and put the car in gear and pushed on the accelerator. In reverse, the motor does not move. In drive, the motor dips quite a bit toward the front of the car. The rear motor mount (the one closest to the firewall), looks fine. Does it necessarily have to be ruptered in order to be "bad"? My experience with motor mounts is only with Saabs, and those you could definitely tell were ruptered whenever they went bad. I have recently had my tires rotated and balanced, too. Thanks for any an all input.
ProfKenn

I am having pretty much the exact same problem. The front seat especially. I had fixed all of my exhaust problems thinking that it was a back pressure problem. I have a great factory service manual that tells me the next place to go would be pulleys/belt systems, but all seems to check out fine. After that, it says to not change/check the motor mounts, but rather instead just simply tighten them. I am meaning to do it this morning. I will let you know how it goes.