PontiacBonnevilleClub.com

2000-2005 Buick LeSabre

I'll be driving along and all of a sudden out of the blue, the engine will shut down for a split second and then resume operations like nothing happened. It feels like the engine locks up solid and the car hits a brick wall. This happens about once a week. No codes stored at all. The closest thing I can think of that feels similar is when I've hit the 108 mph speed limiter; but that gives me a series of jolts instead of one big jolt like this issue does. It's very startling to say the least.

I'm thinking a misfire of sorts. If it happens when the torque converter is locked up, it can be quite alarming, especially if the engine/transmission mounts are getting old and allow some play. At that point, there is essentially a solid connection from the engine through the drive train to the ground, and any misfire can seem amplified under those conditions.

A bad MAF can make a car fall on its face. I'd lean towards that.

Surprised it hasn't thrown a code.
Girlfriend has an '02 LeSabre that had a similar issue. Would stall at idle and buck at partial throttle. Turned out to be the MAF sensor. Easy test is to unplug the sensor and see if the problem goes away.
Scored a new Hitachi MAF on Amazon for a little more than $100.