My 04 sc 5.4 3.73 has only 3500 miles. I have read many post on the vibe. My truck in really actually very smooth except for the 50 to 60 mph. It feels to me to be a vibe that almost feels like a twin screw boat when the 2 motors are not turning the same rpm. Kind of a rum rum sensation the steering wheel does not shake. Does this sound to be the same as the VIBRATION!!!

another note: I had a 86 150 with many miles.great truck very smooth. when the fuel pump went i dropped tank and removed the drive shaft to install new pump. after putting it all back together this truck had a simular feeling. took it all over tried lots to fix it never could figure it out? Just thought i would mention this any ideas?

 

My vibe:

45-60 mph would cause a harmonic vibration throughout the driver's seat and floorboard. The center seat console would also "hum". I could feel it in the steering wheel and gas pedal as well. The buzz in the steering wheel was enough to cause your hand to go numb after about 30 mins if you didn't constantly switch hands.

The vibe was very similar to putting your hand on a speaker that was putting out some bass at a reasonable volume.

There seems to be some fixes out there now. Even as recently as a couple of months ago a case of the vibes was a dead-end street. I hope all with this problem can get it resolved one way or another.

Best of luck.