Engine light on. Determined that gas cap was loose, as per owners manual, for an undetermined amount of time. There was some rain and high humidity. Had about 1/4 tank of gas left from a single filling.
The car seems to be labored at idle (stalled once), but runs fine as soon as you press down on the accelerator. I can also hear, what I can only describe as, a "gurgling" noise from the exhaust. The engine light is persistent (hasn't gone off in three days), but the condition is intermittent.
Filled the tank with high octane gasoline and a fuel treatment (dry-gas). Burned about 1/4 tank, but the condition is recurring.
Any suggestions?