My 90 lesabre did the same thing. When it cut off after driving I sprayed water on the crank sensor and it started right back up. A Buick mechanic told me to do this and this is how I found out the crank sensor was bad!
what can cause a 2002 buick lesabre to not crank
I put a new crank sensor in it, and now it runs great!
under the crank pulley, right side of car under front of engine
Possibly the crank case oil sensor. Had the same symptoms on a Buick LeSabre '91
take it to dealership
It's located on the block, just above the water pump
yes that bolt is keep the balencer mounted to the crank shaft
Happened to me .. it was the crank sensor. Pretty inexpensive to fix
probably damaged the crank sensor, or the tangs on the harmonic balancer
Check Autozone.com or another such sight They might have a picture. They did for the same part for my 91 lesabre. (Which may very well be the exact same part)
its behind the harmonic balancer attached by two bolts but you must first take off the balancer to get to it
try replacing the crank senser,.