my vx has the noise vibration upon de-accelaration since i bought it. It was bone stock, original tires, no mods, 50,000 miles. I took it back to the dealership and they did a service bulletin search and found nothing. They did nothing. I've since done an old man emu lift, torsion bar crank, bigger tires, a tranny flush, rear diff lube, greased driveshaft and put 15,000 more miles on it. Sound is there but has never gotten worse. Like I said earlier, it happens when de-accelerating and It was very concerning at first. But I now don't worry about it.