01 sable won't restart for about an hour

[99caddy]

Hi All!

newbie on this site.

My daughter's 01 sable will start fine most times but about twice a month it will not restart or starts with terrible idle (stalls on drive). If she waits about an hour everything is fine. Had it hauled in the shop and the ran the codes and replaced one of the sensors and assumed it was OK but my guess by the time they looked at it the "hour had passed" so even putting air in the tires would have got it running.

Check engine light is on but I haven't got it to Auto zone to run the codes.

Any Ideas???

thanks