Recently got a 93 corvette off a trade with 105,000 miles. Drove it during the summer and it seemed fine. During colder days (<40), I noticed that it would die at stoplights or after driving in the city for around 20-30 minutes. In addition, I noticed that the car idles high around 1200-1700 rpm and would also shake sometimes. Have recently replaced the air intake gaskets, alternator, Idle air controller , throttle position sensors, fuel pressure regulator switch, and lots of vacuum lines. The car is doing better but still shuts off/almost shuts off at times during some colder days. Could really use some help on what the issue might be. I've heard some recommend fuel pump but that is working correctly. Maybe opti or ECM related? Appreciate it

 

Welcome to the forum.
Have you scanned for DTCs? What is your fuel pressure with the key on engine off and with the key on engine running? Is the fast idle all the time when the temperature is below 40°? Does the coolant temperature warm up to the normal value?
I would check the temperature sensors for ambient, coolant, and oil.