91 mighty max wont start when cold

Next time when cold and it will not start remove a spark plug or two and see if the engines flooded. If so there are two things that come to mind; 1, worn injectors, leaking as engine sits with time causing difficult starts 2: bad oxygen sensor, if failed engines tend to run rich and the ECU may have your injectors pump heavy amounts of fuel to keep from running lean; often times you'll see poor fuel MPG if O2 sensor failed.

I hope this may have assisted you,
Tom