I own a 1999 Park Avenue Ultra. Recently it’s developed a problem where the engine just stops when I’m driving. It happens at all speeds–on the highway, on local roads, in parking lots, or just idling. Starting up the car after it stalls is not problem; it always starts right up. The car stalls at least once a day after it’s all warmed up. Additional stalls can occur, but there is no quantifiable interval between additional stalls. This car has spent most of its 148,000 miles in the upper Midwest. This past winter I drove to car to Arizona, and that’s when the stalling started. One mechanic looked at the car, but couldn’t find anything wrong and couldn’t get it to stall when he took it out for an extended drive. Any ideas on what the problem might be?
I read your post and am wondering what tests were done to the car when it was in Arizona?
How old is the fuel filter in this P. Ave? How old is the battery? If either of these are old replace soon. This doesn’t gaurantee a fix but will eliminate issues down the road. On a older car like this with the 3.8 v-6 I would want to check engine vacume and engine compression.
I would look at the Crankshaft Position Sensor. This can be a problem with any vehicle, but GM vehicles seem to be more prone to this problem.
Have the vehicle put on a lift and raise the vehicle. Start the engine and while it’s idling, take a heat gun and point it at the crank sensor from under the vehicle. If the engine shuts off replace the crank sensor.
+1 to Tester’s comment, as this does sound like a classic GM Crankshaft Position Sensor problem.
As to the other suggestion that this could be due to a weak battery, that is just not a logical solution to this problem. The battery may indeed be ready for replacement, but, based on the symptoms, I don’t believe that the battery is the source of the problem.