*UPDATE*
When I put the car into neutral, the speed goes down normally, not abruptly as if the brakes were engaged. Whatever was wrong has apparently been fixed. I forgot to mention that after the car was serviced for the pad indicator light, the car has been a little quicker and seems as though those rear pads were dragging. How do I prove it? I don't think I can, and I had to eat the cost of the pads and labor ~ $220.00.