The window regulators starting going out around 40k miles. Within 6 mos. All except one rear window was broken.
Around 90K. The transmission started acting up, shifting and thumping very hard, but this has been an intermittent problem, and maybe occur once then not again for several months. If I shut off the engine for a while, it would be fine on next start up. The service engine light would stay on for 2-3 start ups then return to normal.
Around 90K, it started to die on the highway. This seemed to be random and I never knew when it would happen. Usually if I threw it into neutral it would restart without ever slowing down, but on the instances when it did not restart on the first attempt, I would have to coast off the highway and sit for 5-10 minutes. The dealership said they could not diagnose the problem until it gave a service code or I brought it in while it was happening. This problem never gave a key code nor did the service engine light come on when it occurred.
I've had the fuel pump, sock etc., replaced twice. The first time seemed to solve the problem for about 8 months before it happened again. Replacing the pump the second had no effect, the problem still persists today.
As I cannot trust my Buick on the highway I have just today, purchased a new vehicle. I kept my Buick because with the transmission problem, the dying on the highway problem, and only one working window, I felt I could not get a fair trade in price for it.
I've seen many Internet queries about this motor dying problem. I wish they would do a recall to fix it, since it is an extremely dangerous and possibly life threatening issue. Once I was sandwiched between two semi trucks and in heavy traffic I was barely able to get to the pull over lane.