It sounds like a race car and this happens when the speedometer nears 50mpg. What could it be. Hipotheically of course. I was told by a non tech that it could be the transmission. I was also told by another non tech that it probably needed a tune up. 70K miles on it. Oil and filters changed regularly.
How much $$$ are we talking when we talk transmission? The brakes are new, just had them done. Is it time for a new car, this one is turning into a money pit.