After driving for 30 minutes on the freeway, my Sonoma develops a high freq vibration that seems to increase after it starts. lessens a little as I slow, but does not go away until after the car has been parked for a while, but not as noticeable under about 30… I have experienced this the last three days on my commute to and from work. Did have the breaks checked. I did have a clunk sound when i released the brakes at a stop, but that went away after the first brake check where they did not find anything, but just cleaned out the dust and readjusted. The vibe is pretty strong and makes me nervous to drive.
My first thought is a tire that is delaminating. It may not be visible. One way to track it down is to rotate tires and/or use the spare in various locations until the problem goes away.
Since it feels dangerous, your first stop could be a good alignment shop…
How are you feeling the vibration? Through the steering wheel? Through the seat? Through the floor? Is the entire vehicle vibrating?
Based on your description that it doesn’t disappear until the vehicle has been parked for awhile, I’m going to assume that you feel it while stopped and assume that it isn’t I t he rolling stock.
What year is it?
2WD or 4WD?
How many miles?
What type of use?
When was the last tuneup?
Has the maintenance schedule been kept u to date?
Have you had any work performed recently?
Does this year Sonoma have an OBDII system (1996 or newer)? Have you checked for stored fault codes?
Have you checked anything under the hood, like the engine mounts? The cooling fan?
Any other symptoms, like a recent charging problem or cooling leak?
Post back with the answers perhaps we can narrow it down.