Electrical problem
1995 Chevy Lumina 6 cyl Front Wheel Drive Automatic 82000 miles

The Lumina is a APV VAN with a 3.1L V6. I have been getting intermittent fluctuations with the volt gauge. The gauge has seven increments(5 black lines, two red). The lowest line is 8, the top 18. Normally, the needle stays just above the center increment, which I approximate to be around 14 volts. Intermittently, when I am at a stop light at idle, the needle will fall to just above the second line, approximately 11 volts. When I step on the accelerator to go, the needle returns back up to above the 14 volt line. This fluctuation does not happen all the time. It doesn't matter whether the lights are on or not. Everything in the vehicle works fine; lights, windows Air conditioner, etc. To give you past history, in February I had the alternator replaced, because the original one failed. The serpentine belt was replaced also. I did not do hte work myself because I was in another town when it failed. I do not believe that the gauge did this prior to the alternator being replaced.
Also, I want to thank you for the great advice you gave me last month regarding the O2 sensor replacement for my daughter's CRV. It was one of the easiest jobs I ever did on a vehicle!

Steve

Have the charging system tested at any autoparts store for free. The voltage read on the tester should be the same as the gauge.

If everything checks out, take a small multimeter with you and when the volts drop, simply measure the voltage across the battery terminals (engine running). This will tell you if the alt. is going bad.

It could be a bad gauge, but more than likely the alt. is going. They could have installed a cheap remanufactured alt. which can last years or months.