My '85 300 zx has started having 2 problems lately. First, it doesn't seem
to stay at one idle speed. At times it idles around 900rpm but then the next
time I stop at a signal it's idling at 1300 rpm, the next 1500, then back
down to 1200 later. If I turn off the defroster or outside air the idle goes
down. Turn it on it goes up. I would figure if I was turning on the AC that
might happen but it happens even if it's just the outside air, no ac
compressor running. Also, my heater/ac fan no longer works. The light comes
on next to the control button for high or low fan but no air moves through
the vents unless I'm driving. The fan doesn't run from what I can tell. I've
checked the fuses and all are fine. I was thinking the fan motor just quit
but a friend says it may all be related because the heat/ac runs off the
engine vacuum also. Any thoughts? This all started after I had the throttle
body cleaned, which may just be coincidence. Thanks.  Brad