I currently own a 2011 Jeep Grand Cherokee Laredo with the pentestar 3.6. Just after 30,000 miles I started noticing a slight vibration both in the accelerator pedal and the steering wheel. I had just had the alignment done, and the tires rotated and balanced but to no avail. I then took the vehicle back to the dealer. They had it for three full days and found nothing. The only thing I thought of was maybe the tires (Goodyear Fortera), but they've got alot of tread and the wear pattern is even across the tire. The vibration only occurs above 74 mph, and at no other time. It's got me stumped.