we have 1990 lumina with the 3.1. yesterday my son was driving it home from school which is about 11miles and it started surging and eventually died. it restarted and he limped it about 2 more miles before it just decided to not start again. car rolls over and tries to start, but wont stay running. also noticed that fuel pump did not run when key was turned on. waited a while and tried it again, car started. thougt it might be ignition module, it tested good. problem seems to coincide with the temperature of car. when the car is warm is when the problems seem to happen. sometimes when you rev the car up to say 2500 rpms, it stumbles all over itself and dies, funny thing though, after it dies you can hear the fuel pump run like it is priming itself as it does when you first turn the key on. also fans seem to only run when the AC/defrost is on instead of on their own like they are supposed to. I think it is either the ecm, or fuel pump meaning cooling fans are a separate issue.