2004 Grand Caravan. I intermittently hear a "grinding type" noise when going between 25 - 30 mph. It mainly happens when you are stuck at the same speed. As soon as you speed up, it stops. I also sometimes feel a vibration in the accelerator pedal when then noise happens. Dealership continually says no problem, it is normal. However, all the rentals we have had do not do it. Anyone else have this problem?