Check the "mass air sensor". Sucker drove me nuts for over a year and condition got worse and worse.

 

does the 84 even have a Mass air flow sensor i thought that was only on the fuel injec models....could be wrong but anyways from what i know there is some small cylinder thing on the firewall that has something to do with the choke.....i hade the same problems i ended up pulling apart the electric choke and putting in a manual choke lever.....honestly the choke is only really needed in the winter to get the car to start.......might want to check into that if you can't find anything else out......another thing the temp....check the relay that should be on the driver side aginst the firewall...mine went bad and kept blowing up for some reason so i ended up getting a seperate device that will tunr it on u hook it to the batt and put a copper tube into the rad. and its even got a variable temp adj. to it.....works out reallly reallly well for when u get stuck in traffic and it also has another connector to hook a switch so that u can manually turn the fan on when ever you want.....i got it at a local parts store for like 20 bucks and been running good for about 3 yrs now...