I was told last weekend that I likely had a broken motor mount. I was told you can check by putting the car in gear and power braking to see how much the motor moves. How far (I'm thinking not very) should the engine move when you're dong this? In drive (doing this myself) the driver's side of the motor, looking mainly at the air cleaner) moves up over an inch, maybe even two! In reverse, the passenger's side moves up about the same amount. It seems to me like an excessive amount of movement, but I've never checked my motor mounts that way before.
Sounds like excessive movement to me. Maybe check out replacing that mount even if it isn't completely broken. -Corbin