By chance have u tried adjusting the throttle cable or tried adjusting the small screws on the throttle body/fuel delivery system? if so, according to which one there is good news and bad lol. If you just tried to adjust the idle by the cable unit then most likely you have it out of sync with the other side of the cable. I mean there should be 2 adjusting screws on the throttle arm. Mine has a top and a side/bottom cable if u tighten one, let's say the top one (the most obvious) to where it stops before bottoming out.. like back in the good old days with carbs, then the side/bottom cable adjuster is way loose, if u tighten it then the top cable will be way tight. it has to be equal on both sides so to speak. look up the throttle cable adjustment specs in your Haynes or Chilton manual etc., then follow how it says to adjust it properly.
Now, the second question about the small screw adjusters for the air fuel mixture, if you have changed it by turning any of those on the throttle body/fuel rail etc.. then u will most likely have to go to a shop to get it all resynced. its synced at the factory and there really isnt a layman way to reset.
How i knw this is because i'm havin the same or similar issue with my 1990 2.6L (4G63) it was not shifting right and seemed to be idled to slow, oh also check timing and make sure that it is correct, anyways, i only tried to adjust the cable, well afterwards it was lobbing afterward, so tried again, well got better until it get reg oper temp came out of fast tik, then the wheels would slide to a stop, tried a 3rd time, now its back to lobbing a;little but coming to a stop light/sign it will idle down so low it almost stalls. If i have to wait too long it does and then i have to start it again etc. So its in the cable adjustment for as my issue. So check that avenue as well. but stalling is because of it not receiving enough fuel and or not in adjustment of the delivery system. also make sure ur distributor is set correctly.
Hope this helps
regards
Knight