92 S-10 Blazer. Engine light on, starts a little rough, then smooths out 1-2 min

What is your question?

Runs good when warmed up and idles good as well. Ran diagnostic and couldn't come up with much except something regarding the ecm. Mechanic thought it might be a temperature sensor at the carb but I can't find anything like that. Could it be the throttle position sensor? I'm at 5000', car has 225k miles, new fuel filter.