vibration

i have 1999 toyata avalon and is given me a lot of headech, the engine vibrate and shakes terribly when driven or slow down or speeding up. i appreciated for any ideas. thank you.

You might want to post this in the Toyota forum so people see it. This is just the introductions part of the site.

Without knowing much about your vehicle, the first thing that comes to mind is the spark plugs. Have you checked/replaced them recently? How is the oil level? Things you should ask yourself so you can eliminate the easy stuff. You could also try describing your problem more thoroughly.

How many miles are on it? When was the last time you had a tune up?