93 Bronco - idling problems

I have a 93 Ford Bronco. Engine runs fine when it is idling
but when I turn on the air conditioner or the heat the RPMs
drop and the truck wants to stall out (and sometimes it does).
Also, at idle, if I step on the gas pedal and when the engine
'comes back down' it also wants to stall out. This just started
happening. I had the alternator tested and it checked out
good and the battery is fairly new.

Any ideas on what I can do to find the problem? Ideas what the
problem may be?

Thanks in advance,

Mark

check Big Broncos Club... thousands of
diy tips and chat... also, some on Yahoo (groups)
aso f150.com is the same truck. maybe a dash between the f-1?!