normally in compliations, the fwd mean Front Working Directory. this should be your table of contents, probably named fwd.pdf or something. i believe you can access the index from the fwd, ive never used the index. remember, you need to download all those pdf files, the fwd will just link to them. once youve opened them, just save them to your computer, for future access. they will be your best friend.
there is no vacuum going to the heater? its an electrical connection, and the heater core uses coolant. this is why im trying to isolate the problem, its unlikely that your heater will cause a loss of idle, unless your charging system is very poor, and that little voltage is causing a drop. however, if youre using the ac, or defrost, there is a large voltage drop, also tension added to the pulley when the ac clutch engages/disengages, which should change your idle, but not lose idle. the tension added could be extreme if your ac system needs servicing, and could possibly outwit your ecu to lose idle.