1999 Pontiac Bonneville Randomly Kills


Engine Mechanical problem
1999 Pontiac Bonneville 6 cyl Front Wheel Drive Automatic 123000 miles

Car dies at random times (no specific mph, turning, stopping, slowing down etc. Purely random). This happens with no check engine light on. I have had diagonstics ran on the vechile and have replaced the fuel filter, fuel regulator, throttle positioning sensor, mass air flow sensor. Wondering what the next logical step would be? I have heard (from my friend who has been a mechanic for 7 years) it could be a short in the computer or possibly the crank shaft sensor. Need help!

Do you
have the same problem?
Friday, January 16th, 2009 AT 7:47 PM

1 Reply


Hello -

To better assist you is this model a SE, SLE, SSE, or SSEI? Also please let me know your engine size in liter.

You said you had diagnostics ran. Does that mean you have had the codes checked?

When it dies there may not be a check engine light but are all the dash lights still on?

What I would like you to do please is go to Auto Zone (AZ) or O'Reilly's (OR) and for FREE they can pull the codes to the car. Most important: Once they check your codes, if they find something and you don't get it fixed and need to get back with us, please make sure you tell us exactly what the code was, number and all. Example, if the code was E0568 O2 Sensor bad. Then make sure you give us all of that. While there for FREE also they can bring their tester out and check your battery and alternator.

We need to figure out if it is electrical or fuel related. When this happens pull a plug wire off of the spark plug and insert something into the end of it and have someone try to start the car and have the metal object really close to a piece of metal on the engine and see if you are getting a good strong popping blue spark. Don't have your hands on any part of the metal! If there is no spark, then it is electrical.

If you are getting good spark then spray some starting fluid in the throttle body and try to start it and see if it tries to start then.

You may need to get a fuel pressure check on the fuel pump to ensure it is putting out okay. We will see.

Also please try this and let me know what happens. Slowly turn ignition switch from ACC to ON, does the dash lights flickers or goes off? (Yes or No) Slowly turn to START, does the light flickers or goes off? (Yes or No) When cranking the starter, is the battery charge light ON all the time? (Yes or No)

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Saturday, January 17th, 2009 AT 8:40 PM

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