I noticed a problem a couple of days ago while driving home at night.. my dash lights dimmed to half their brightness, headlights etc.. and the vent fan slowed down for about the same time period that my revs were above 3500rpm. And this was while xlr8ing up a highway ramp. Whenever i downshifted to bring the revs up, same thing kept happening. The battery light never came on. It was pretty damn cold that night.. (-24C, -12F)
When i got off the highway and stopped at a light, as my revs were going down (no TH fix) something in the engine compartment was making a periodic whiny-metallic-rubbing sound that lasted about half a second and repeated every half second as the revs were dropping to idle... kind of like a whoo... whooo... whooo... type thing. Each "whoo.." was accompanied by the same light-dimming, fan slowing that happened at high revs. This still happens at every stop.
My first thought is the alternator might be dying... I do have a funky-wicked stereo in the car that draws tons from the electrical system, I'm also thinking that helped in the alternator's demise.
If anyone else ever had the same problem, I'd appreciate any input on what it turned out to be and what it cost to fix.
Thanks.