I have a 2001 ES300 with vibration that comes and goes, most notably above 40 mph, even on smooth roads and freeway. Most noticeable on driver's side. Replaced two wheel rims, four tires, motor mounts, and the mechanic clears the rotors and suspension after replacing some parts. Tires have been balanced at five places including dealer. Today the TRAC and CHECK ENGINE lights came on, and for a while the steering wheel vibrated with braking from 40 mph and not at 15. Then this stopped. Any suggestions? Thank you.