1984 Buick Skylark Custom with Stalling issues

1000 mi. On rebuilt motor, new: transmission, fuel pump, distributor, ignition control module, vacuum hoses, radiator, & carburator. 2.8 L v6, automatic. Runs great until it warms up and then sputters and stalls. Will restart again after it cools down again. Out of ideas on what else to look for. Diag shows no errors. Can you help?
Car will restart after it stalls but you must wait for it to cool down before you can put it in gear and take off otherwise it dies again. Stalls only after you come to a stop and not when driving. New temp sensor installed.