Betchya it is the alternator going...thats exactly what mine did, if it goes into "battery saver mode" then I REALLY bet that's what it is.
I got an electrical burning smell in late September and once more in November, nothing ever came of it, and then this Monday I started getting all kinds of faults, ABS turning itself off along w/ ESP, battery save mode, alternator light, speedo/tach dropping etc.
Bad alternator was the culprit
'08 GT sport/premium, tints 20/35, 18" TSW nogaros w/ bridgestone blizzak winter, 19" sport oem w/ hankook evo summer, Philips crystalvision bulbs, debadged, Vararam OTR, JBA 1-3/4" LT's, ported TB, MF axlebacks, MF X-pipe, DBA-powerslot brakes, russel SS lines, hawk ceramic pads, GXP shocks/struts, lovells poly strut mounts, Slowhawk Tuned 344/356
Gone -'04 GTO A4 2.5" custom exhaust, sweet thunder muffs, H pipe, Z06 heads, Baer brake it, 20% tints, torrid red, AEM brute force intake, tuned