You may want to change out the motor mounts anyway depending on how old they are. But Im sure you'll still get the same thing. Mine would happen between 60-70mph. It would only make a slight vibration when I accelerated between those speeds. I could feel it in the steering wheel and the pedal. Anything below 60 or above 70 it was fine. I went the whole alignment, rotation, rebalancing route, but none of that fixed it. I found out the problem accidentally when I drove through a whole bunch of nails and had to replace all my tires. (they were still new, only 10k miles on them) Once replaced, it was gone completely.