Car stops while driving.

06 Buick Lucerne
While dirving the car will just stop running like turning off the key, coast to the side of the road, place in park & it will start again. You never know when this will happen. It has happened four times in the last two weeks. Buick can't find a problem.
I thought it might be a in-line fuel filter but can't find one. Would a bad gas cap cause this problem? Any ideas? Thanks Rick

Welcome to AF. Gas cap no. From here there is no way to diagnose this, I assume the dealer has checked for related TSB's. Does this happen coasting or slowing down, hot? cold?

Thanks for the reply,
It is normal operating temp & in town driving approx 40mph the last few times.

This is one of the few things that has never happened to my Lucerne, but not contradict
maxwedge, the gas cap was the culprit causing a previous Buick to do the same as yours. Apparently the vent in the cap was blocked and created a vacuum in the tank. This was some years ago, so maybe now the computer might detect this and show a code.

I also own a "06 Buick Lucerne and its mileage is around 38000. During the past several months I have experience the same problem of the car cutting off while diving. The first 2 times the dashboard remain black when I turn the key but yesterday everything lite up (all possible warning lights) but it still would not crack. Later after many failed attempts it decided to crank right up. I have brought it to the dealership and also another garage and both did not know what cause it to happen. Saying without any codes they don't know what to do. Someone please help, this is dangerous and might cause a lot of money to correct. Thank you

"Intermittent" problems are the hardest to diagnose........if you can't recreate it, you are at the mercy of the person giving a full description of what happens.....

Basically, a bulletin search, a test drive, and visual inspection is all you can do.....more than likely, it's an electrical connection.....sometimes you get lucky pulling on the right harness......

Can't say it couldn't happen, but the gas cap shouldn't cause this problem....the gas cap is a seal, pure and simple.......what causes a vacuum in the evaporative system, is if the purge and vent valves are not working correctly or a kinked/blocked line....high vacuum should cause a code to be set......