[Beav]

After a little more thought I've ruled out the wheel bearings, as you stated it can occur with the car parked as well. That indicates that the cause of the pedal vibrating (and the shifter has a noticeable vibe if you have your hand resting on it) is something that is causing the vibration to transmit to the firewall. I've been suspecting that my engine mounts are sinking, maybe they're squashed to the point that they are allowing the engine to pull the torque strut (behind the throttle body) and load it against the firewall. Hmmm.... maybe I'll just remove the strut and see if anything changes...