i still would check out the air valve, just takes a few minutes. the only reason i'm suggesting it is that u say the idle is stuck at 2000--that's exactly where mine is at when it's cold and on high idle
i just drained the coolant a couple weeks ago and when burping it, it was stuck at 2000 rpm even w/temp guage showing warm. i shut it off and restarted it a couple minutes later and idled fine. the reason is because the iac determines how much air gets by going off the coolant temp, and w/an air bubble, it had nothing to warm up the iac so it would slow down the idle--mine is a 93--according to alldata, your 85 is set up a little differently--it uses coolant and is supposed to also have a bimetallic spring in it (like a choke pull-off) that works off electricity--should have 2 wires--i'm wondering if the spring somehow got broken when u were taking the intake on and off, if u got a little rough w/it, and since u can't see the spring, didn't know any different
obviously i could be way in left field, but since stuck at 2000 that's the first place i would have looked
good luck--oh, when i had the air bubble, it would drop to normal and shoot right back up every couple of seconds.....
