Gas Pedal Vibration

Well buyer beware ...Wish i found this site before i bought my 2000 Intrepid. Anyway ran great for the 1st 2 weeks now its going down hill Fast. First had to replace 4 Warped Rotars and Brakes and now today its in the shop for Not Shifting and no Speedometer. A nagging question on my mind for this 2.7L enigine is what feels like a low freq vibe in the gas pedal. My foot was actually starting to itch driving 60 MPH for about 45 mins. Any Ideas on this?