i know in many newer vehicles the check engine light will come on if you dont tighten your gas cap all the way down. well over the past week in my 93 samurai i had my check engine light come on and go back off and today realized my gas cap was loose, real loose. could this have been the problem?
It's much, much more likely in an OBD2 car. OBD2 has a sequence to test the vapor purge system for leaks (which could be caused by a loose gas cap.)
On an older system, you would need a big enough leak to cause a lean condition (due to too much air being sucked in)
The chance are probably pretty slim (you'd probably have to leave the cap all the way off and/or have a cracked hose somewhere), but the possibility does exist.