<p>Reader Question

I have a 1994 Buick Lesabre that dies at random times. it will run fine then the motor will shut off and oil, temp, and the other normal warning light come on. It usually starts right back up, but some times it will run rough for 15 seconds or the rpms will fluctuate a bit.

On a typical run to the store (bout 1-to 1 1/2 mile in the city) it may happen only once if at all. Other times i can happen every block or so. i have replaced the fuel pump, fuel filter, camshaft position sensor, crankshaft position sensor, the timing chain and gears, water pump, idle air control, (cleaned out the throttle port where the IAC is located)

Any possible ideas you have the might cause this problem would be greatly appreciated. its my daughters car and she isnt able to use it beacuase of this.

Thank you, Daren.

Hey there Daren,

Wow man, you have replace just about everything on this vehicle. This is a VERY common complaint on these vehicles, and 9 times out of 10 a faulty crankshaft position sensor is the culprit. Did you use an A/C Delco sensor by chance? Before I spent more money, I would install a genuine Delco crank sensor just to rule out the possibility of a faulty new sensor…..which I have seen before, although rare.

I would also do a “tap test” on your ECM computer. With the engine running in park gain access to the computer under the passenger glove box and lightly tap on the surface of the computer with your fist. If you notice any change in engine running replace the computer with a rebuilt unit you can get from a local auto parts store.

Also, I would look at the ignition module, located under the ignition coil pack. I would assume you have the three part ignition coil system with the flat ignition module underneath.

Make sure the connections to the coils and the module are in good shape and there is no corrosion. When the module fails it will produce erratic symptoms like you describe but usually the engine will not restart easily since the module overheated and needs to cool down before things work again.

Those are my 3 top suggestions, let me know how things work out.

Blessings,

Austin Davis