I have a 2007 edge sel plus AWD.I've had it for about 2 weeks and I noticed the engine making a loud deep revving noise when excelerating.It seemed to get worse the past couple of days.I can feel the vibration in the gas pedel.I went back to the dealer and test drove another edge, makes the same wining noise, but it doesn't have the deep revving noise.Is there something wrong with the negine or is it just the braking in period?