My winnie exhibited similar problems, it would occassionally buck at hwy speeds and die at idle. In my case it ended up being the mass air flow sensor. No codes were ever set. When the problem became quite frequent I tried cleaning the MAF, that helped some so I bought a used one for $60 from a boneyard and havent had a problem since. Again the bucking was intermittent, not a continual problem. Another area to consider is the camshaft synchronizer, is there a whine coming from the synchro, if so pull sensor off and see if there is any damage evident, if so the bearings in the synchro are bad. Others have had problems with the fuel pump relay. In the 2000 the horn & fuel pump relay are the same, try swaping relays. Just a few thoughts for areas you haven't considered yet.