I've had my car since August. Drove awesome until November. Starting noticing a hesitation/vibration with the engine when trying to drive an maintain a speed. For example if i'm driving 30 mph and just try to keep at 30 by applying slight constant pressure on the gas pedal the engine will start to shake. Reminded me of when i needed a fuel pump on a previous car. Had the fuel pump tested and its fine. Since the issue i've also noticed my MPG has decreased. We would typically get 26-28 MPG on the highway now we're averaging 21-22 MPG highway. I've had in the dealership 3x and they say the vibration/hesitation is normal and how RDX drives. I've driver others when car is serviced and its fine. The Head Machanic said he can definetly tell their is an issue but they have no answer and Acura Corporate Engineers say thats just how they drive. I need help and suggestions?