It started in the spring and I'm not sure where the vibrations are coming from. The have not been able to replicate it. I get the vibration at the same rpm range that you did, around 1,500 rpm, getting louder until about 2,000 then it stops. It doesn't happen all the time. There's another dealership closer to work that I'll try in a few weeks. If they fix it, they'll have my business from now on.