Driving home last night my battery light came on. The dash lights got dim & the gauges went wonky- the amp gauge went to almost nothing, gas went to empty - then back to 3/4 ( which is where it should be ), The tach now stays at 1200, but will go up slightly if I give it gas. Today it rolls over very slow, but if I turn the key to the on position and hold for a sec, then in start mode the engine starts right up. When I give it gas the battery light comes on. I know I have read something about what is causing this - but I can't find it again. Anyone have an idea ?