I've got a 2000 Ford Focus SE wagon with about 90k miles on it now. For the last year it has been vibrating and humming or throbbing loudly. It seemed to only do it in the winter cold, but now does it all the time. The throbbing vibration starts just above idle and resonates inside the cab of the car so loudly at a low frequency that it will literally make you sick. If you get the RPM up high enough, it isn't that bad because the frequency of the vibration is too high to resonate, but you can still feel it in the steering wheel and if you put your hand on the front of the car anywhere. It feels like a car with no muffler. I've hear "exhast system", "flywheel" and "torque converter". Anybody have any ideas? I do not have to be moving. Just sitting in park or neutral will rattle your teeth if you get the RPM's above idle.
-f