On my trip home tonight, when I was on the on ramp, my battery light came on but only above like ~3500 rpm, then goes off after. There is a rattle somewhere behind the cab and it vibrates like a massage chair now. On top of the spare tire thing, this thing has just fallen apart since it hit 90,000 miles. Any ideas? I was thinking maybe the alternator is getting ready to go, and I guess I will have the tires rotated and balanced. This thing is really bumming me..