[rogerh]

So here's the update....the start stop button was indeed broken and replaced, and after two days and many Buick Dealer Service "Tech" personnel taking our new 2023 Avenir for a ride at speeds over 70 - 85 mph to try to hear the same creaking / rattle noise?, they heard it, and they found it, the noise comes from two splash pans, located directly below the right and left front seats, they measure 24" x 36", and when tapped from below on a lift, make the same noise. These pans are thin plastic, and at those freeway speeds cause them to vibrate. And it's because there is not any sound deadening material at all under the car or on these plastic panels to absorb the vibration. They even found the same issue on any FWD Envisions ( they claim the AWD do not have these panels ) on their new car lot. So did they "offer" to correct it? Nope, they said "you can remove the panels and it will work just fine" , ah No, not going to happen, So I called Buick cares, and they documented the Noise issue,as well as the knucklehead service advise. Then my wife and I put the Buick on a lift at home, removed the plastic panels, and used aluminum backed sound deadening material to cover the underside mounting points and some of the center and end areas on this panel, both left and right. Put our car back together and guess what?, No More Noise at any speed up to 95 mph ( that's as fast as I cared to go on our highway for the noise test ). Hope this helps, but and as to Buick helping, Nothing

Could you give us a better description, model number or picture of the "aluminum backed sound deadening material" you used?