Under normal driving conditions the voltage gauge will drop down to 8 and the red (check gauge) light comes on. This has happened at idle and at a fixed RPM such as 70mph with the cruise on. I have had the alternator-changed cause the dealer said that was it …WRONG….and at an idle the car run very bad…pops stumbles and misses. NO SES light yet…..
This is what I have done.
Unplugged and replugged all wires…all ground wires removed and I ground the contact area down to bare metal…Battery was checked …GooD…NO wires have been cut on spliced and no electrical mod have been done. Stereo alarms…and so on.
I have other ideas on what to do next but I would like some input. New belt…. Check alternator
T.A.S.
runnin away - 
phantom problems are just not worth the headache of chasing. On the other hand, if wiggling wire worked, the problem may be in the wire connection to the plug rather than the plug to plug connection.
Wiggle in the dark ... maybe you'll see a spark at the bad connector. (let's see where DanEh goes with this line)
I had a 70 Chev 1/2 ton with an intermittent no start problem that could be overcome by running the Genie shifter through the gears ... had no idea why. One day I hit the shifter hard in frustration, and saw a spark ... the neutral safety switch connector was broken, but hadn't moved, so it still made contact as often as not.
Do you also see these problems when the A/C is turned off? I'm wondering if you could be having problems with the electric clutch on the compressor.
T.A.S.
Actually, I think Possum has a good idea. Although it seems to me that there might be something that has an internal short. I had hoped to hear the alternator did the trick. I am sure that already checked the regular stuff like the battery connections. How about things behind the dash like radio connections? How about the voltage regulator. Do you have Auto tap? You might be getting codes that haven't thrown a light yet. Sometimes the light won't go on unless you have the problem x number of times. If you only have an intermittent, it might clear the code before the light comes on. Autotap can read the history. This sounds like a tough one! Good luck TAS.
