Idles at 4 grand!

I have an 89' dx, automatic. The damn thing started idling at around 2000 rpm's about 2 weeks ago. A week ago it moved up to three. I tried adjusting the timing and the idler screw, but it didn't effect it. Oh and it went up to 4000 rpm. I adjusted them back to how they were before I messed with them and it didn't make a difference. What the hell can I do to fix this? I know my way around fuel injected cars very well, but this is carbed and I really don't know much about em cause I've never had to work on them. So any help would be greatly appreciated.

You just have to get an eyeball on the linkages and determine which is causing it to hang, and then figure out why that is. Common problems are a bad or sticking choke pulloff mechanism (the diaphram that has linkage to the choke plate)...when you pump the gas pedal with the engine cold, the choke plate should close all the way, the as soon as the engine starts the pulloff should suck the linkage in a bit and open the choke slightly...as it warms up the choke pulloff should work against the thermostatic spring to open the choke plate more and more as it warms up...stepping down the idle incrementally as it does (you'll see a related linkage with a stepped throttle stop)

If you don't see any of this, by '89 they may have been using a dashpot electric kicker to step the idle...sometimes they go crazy and get stuck fully extended...you'll see it pushing against the throttle plate linkage, keeping it from coming to rest on the idle stop screw (the one you adjusted)

Check for vacuum leaks too, that'll make them rev ridiculously high...and make sure the coolant is full...