Motor dies after warmed up

my 1988 Chevy SprintMetro’s motor has started to die after it has warmed up. I took it into a reputable shop and they cleaned the choke and replaced the air filter, fuel filter, and added a fuel treatment. They said the oil was dirty and advised oil change & a new oil filter. That has since been done. They said it would go further, but it would still stall. They are right. It goes a bit longer time - but it still stalls after it has warmed up. It has 92,000 miles.



Any ideas of what the problem might be?



When was the last time it had maintenance, like plugs and plug wires, fuel filter. How about the thermostat?

A long time ago - I’ll go ahead and get new replacements and see if that helps - if it doesn’t it is still things that had to be done - thanks for the reminder - much appreciated.