Originally Posted by SolRayz

I have the infamous harmonic rhom rhom rhom vibration between 70-75mph (around 2100rpm) while accelerating. I can feel vibrations in the gas pedal and on the floorboard beneath my left foot only. There are no abnormal noises when accel, stopping, or turning. Its only vibrations at highway speed.

The wheel bearings seem fine, no play or noise. U-joints on the driveshaft maybe? The slight driver side CV wobble possibly?

I've replaced left and right front and rear suspension
Both LCA's
Both Inner and Outer Tie Rods
Swaybar endlinks and bushings
4x firestone Destination AT/2 Tires
Balanced and rotated twice, last being at Toyota
Alignment at Toyota.
Both Diffs, Trans, and Transmission drain and filled within the last month

Truck drives smooth otherwise. I've been researching this for a month, and throughout the forums, nothing has been conclusive on this harmonic accel vibration.