Q: My car keeps shaking and vibrating when ever am at speed and when ever I apply my brake. What can cause that? 2008 Toyota Highlander

Hi there - there are 2 issues here: what is the source of the vibration, and what is allowing it to continue or even be amplified? The source of the vibration could be a wheel/tire imbalance or a failing front axle or Constant Velocity joint. If you put the car in Neutral at highway speed and let it coast down (without touching the brakes), does the vibration continue? If so, it is likely an out-of-balance or bent wheel/tire. If the vibration is reduced when doing this, it is more likely a worn out axle or CV joint. If the problem is worse when braking, the issue could be "warped rotors" or worn suspension control arm bushings. Worn suspension components are what allows the problem to continue or be amplified. I recommend a vibration inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.