Engine Shut Off Without Warning problems of the 2008 Buick Enclave

Various problems with electrical. Had harness replaced (come to find out its due to water leak). Air bag sensors go off and on so you really don't know if its working or not. Engine shutdown completely and now when its started the engine makes loud knock. Was told possible timing chain. Only has 140,000.

While driving the vehicle just shuts down. The first time it restarted, but on the second occurrence it would not restart. The vehicle has "stalled out" several times while traveling at rates anywhere from 25 mph to 45 mph. We have had it towed to the shop (including the dealer) 3 times and are told nothing is wrong. But the problem happened again today. I see other people are experiencing the same problem. Although we have avoided it thus far, it is going to cause an accident.

On Aug 20 the truck in front of me with a hitch stopped; so did I. The car behind me and the car behind him didn't stop. I took the car to springmall auto body in springfield - $5500 worth of damage. One week after I picked it up, I was driving and the engine shut down. I got on onstar and they said the traction and abs control module failed. I took it back to springmall. Because it's so new, they drove the car to where I bought it - rte 1 pontiac, gm and Buick, woodridge va. Upon receipt of the vehicle, the mechanic never asked for paperwork from the autobody shop who delivered it - they had no idea the extent of the damage. The mechanic said he needed to drive it home to see if it would do it again. The next day, they said they fixed it and told me to pick it up. One week later after a 2 hr ride to richmond - it petered out again and I had to dive for the breakdown lane. I brought it back to rte 1 Buick and they said they would have to keep my car (which I am leasing) and apparently it was something else wrong. I asked them to immediately call springmall and get a fax of the accidnet and extent of damages - they were shocked. I said I didn't mind leaving it, but I wanted my miles refunded. They said no. The whole scene turned ugly and they told me to leave the shop. I have a pregnant daughter and a granddaughter who ride in that car a lot - why did they tell me it was fine to drive if it wasn't? the car just stops!! the head mechanic said the only thing he could do was put a black box on my car, which he did. That was over two months ago and the problem hasn't occurred yet. He said just becuase onstar said what it was, that may not be the problem. They told me to stay in the slow right lane and if it occurs, push the top of this plugged in black box and head for the breakdown lane. I never know when it will happen, and I am scared to death. Please help me I have a new car that I can't drive; it may even take the lives of people I love.