My 04 TL has 74.3k miles, bought used in March 2010. The trembling is not earth shaking but you can't miss it. Once it hits 40 mph and beyond, the car's just fine. Since I put in regular gas at first so I thought this must be pinging so I switched to premium. But the problem still exists. Is it the motor mount as I've read from other comments? Or new transmisson fluid would cure? I haven't check the fluid's color yet. Any advice is appreciated.