Pontiac Repair: 1995 Pontiac Bonneville, voltage drop test, ground cables

Question
My 1995 Bonneville will start sometimes, but other times it starts but check engine, traction off, check gauges lights and volt meter for battery shows in red then it dies after a few seconds. After trying several times, it eventually starts and alert lights go out and battery shows around 12-14.  Then must let warm up or alarm dings and lights come back on and it dies.  No one can tell me what is wrong, since it doesn't do it all the time.  What could be causing this problem.  Changed fuel filter, battery cables, had coil pack and battery tested all ok.

Answer
Hi Mary:

Well it seems like you have a low voltage issue here either from a bad connection or a loose connetion or a battery that is not up to snuff. What I think is happening here is the voltage threshold is dropping to low and the engine computer and other modules see that low voltage and are setting various codes dur to that. I would have the battery load tested a couple times in a row to make sure it will keep it's voltage up. then I would check the ground cables both on the block and on the body. that car has 2 battery cables on the (+) post and at times corrosion builds up in between the cables and causes all kinds of wierd problems. if that all checks out good have your mechanic/technician do a voltage drop test on the (+) and (-) battery cables. lastly have the alternator checked to make sure it is producing the proper amount of amerage especially on a cold start and go from there.