Slight Vibration in Gas Pedal???

[Tony721]

I recently noticed a slight vibration in my gas pedal. It almost feels like an engine vibration, and gets worse at highway speeds. The truck is an 06 4wd CC, 6.0 of course, automatic. Both front wheel hub/bearings are new, all ball joints are new, so basically most of the front end is new. Running Kuhmo 285/70/17's. I have had them on the truck for about a year now, rotate every oil change (5k). The truck runs great, I'm just not sure if this is motor related or tire related? Just curious if anyone else has experienced this, and if so what might have been the problem?

Thanks