well, somethin like this happened to me, does it feel like you have loss of power when you try to accelerate?
some of the symptoms you describe are problems i had ( except the stalling on teh hwy) the day i was takin it to my friends out, it wouldnt start, it just kept clickin and tryna turn on, then after trying alot it drained my battery.
my problem was the cat convertor, it was really clogged which caused back pressure to make my timing jump.
do you have after cat or anything?