[Davescort97]

Ford has a technical service bulletin out on the motor mounts causing more engine noise than usual. It is about a $300 repair and some doubt that it solves the problem. If you have an automatic transmission the torque converter lock up could be at fault. At speeds above 40mph the torque converter is supposed to go from a fluid drive to a direct mechanical drive for better gas mileage. An electrical solenoid actuates the lock up. If it's not locking up into a direct mechanical drive the rpm's will be higher as you well know. Take it to a transmission shop and they should be able to diagnose it for you.