What might cause a '97 Nissan Sentra GXE to vibrate a lot at speeds above 65 mph and how can it be fixed?
A common cause of vibration at speed is unbalanced tires. Maybe you want to look into that and also check on the car wheel alignment if the steering does not stay on a straight path on a level road. one possible answer is the belts in the tires may have slipped. check with tire specialist to be sure. Ask them to check all 4 tires because one slipped belt will cause problems. I drove my car with this problem for almost a year before I got the right answer. replaced all 4 tires and now it drives nice and smooth.