I think I've narrowed down my problem of shaking idle and bucking to the engine or tranny mounts. I can see the engine shifting. When I have the car in park, and manually rev the engine with the throttle cable, I can see the engine pick up and drop back just a little. The movement is obvious on the front mount- down below the exhaust manifold. It moves up about 1 inch then drops back down again when the engine first revs. Is this a true sign of a bad mount? And if so, what am I looking at for price for replacement at a garage?