Hey guys, I am in a real pickle right now. The problem is when I am on the highway at speeds over 55 mph wide open throttle, the truck shakes and makes a droning noise under the vehicle. Now when I leave off the throttle completley the shakiing and the noise stops. I am pretty sure the car is not misfiring, cause the plugs and wires are pretty new. It definetly sounds like drivetrain problems, any input from you guys would be greatly appreciated.
Thank YOu
JR

 

Try putting the truck up on a lift, supported by the frame, so that you can check out the drive axles' universal joints.