Why would an 86 Camaro suddenly lose the ability to maintain idle upon start up?

Answer 1

AnswerI believe it has a carb and if it does, it is probably the auto choke. The choke can cause this but the vacume to the map sensor or the map sensor its self could cause it. try looking for any open vacuums spraying carb cleanes on the lines will make it idle up and locate the culprit if its a vacuum.

Actually, you need to know the engine size specifically and specifically if it is carb or not. If it is electronic fuel injection check for an open or short in the IAC or the IAC could be bad. IAC=idle air control valve. Another question, is the check engine light on? This is all need to know stuff in order to answer your question without guessing.