Alright, this one has me puzzled. normally i can figure out what things are by crawling under the truck, or by listening, and feeling what its doing. but this one has me baffled. at higher speeds, 60+ mph, when im on the throttle, light or heavy, i get a vibration in the pedal and the seat. which makes me think its in the rear. steering wheel doesn't vibrate. however the gas pedal has the same feeling, which makes me think its drive train related. its not a huge vibration, its subtle, yet you definitely know its not normal. i can be going 60 mph, accelerate and i get the vibration, the second i let off, its gone. so it doesn't seem to be speed related. checked the tires, all tight and no wobbles, checked the drive shaft, same thing. its all good. any ideas? im not overly mechanically inclined yet, but im working on it. just need ideas on what to look for. hope i explained it well enough.