Hi everyone! I have a 2006 Highlander and have owned it since 2007. 3.3 v6, been an awesome suv, but lately, after its been sitting overnight, or after a days work, when I start it, it makes a loud humming sound, like a loud vibration from the front, under the hood. It only happens on the start-up, never when the motor has been running. Any idea whats causing this?
thanks, Frank