voltage problem

[firebirdlt4]

what would cause my battery guage to drop down into the red and my check guages light comes on when getting on my car. It don't do it until around 4500 rpm and up. When driving around normal it won't ever do this. Also when driving my tach will be bouncing up and down. Say if i was running about 2500 rpm it would be bouncing from about 2000 rpm to 3000 rpm.

[SVG210]

what would cause my battery guage to drop down into the red and my check guages light comes on when getting on my car. It don't do it until around 4500 rpm and up. When driving around normal it won't ever do this. Also when driving my tach will be bouncing up and down. Say if i was running about 2500 rpm it would be bouncing from about 2000 rpm to 3000 rpm.

okay do you feel the engine doing anything diffrent? if so there might be a short

if not its probably your Cluster Either its going bad or theres a short somewhere, and when you accelarate it sends more current.

[blue02Z]

could be the alt. going south. check your output current and voltage on the alternator while revving it up

[jamessr]

I suggest finding out exactly what your alternator putting out. To do so you'll need a multimeter. I understand it only does it while driving and at 4500 rpms. However I'd still hook up a meter and rev it up and see exactly what your getting 1st. It could be a faultly gauge or it could be a true electrical problem. If its confirmed you voltage is dropping like you say it is, I'd check for loose connections. Ex alternator, gauges anything like that.