If it is the gas cap, the computer (PCM) will relearn the normal code after throwing the code. It took a few days and key cycles (start and stop) for the SES light to go off in my T/A after I replaced the MAF, O2's or TPS.
Unplugging the battery IMO is not recommended as the entire car may have to relearn ALL the settings (A/F ratio, throttle settings etc.) over the same 40 or so cycling starts and you are only prolonging the fix. Car will run rough until relearns.
This is a simple problem that with a few days should fix itself. If after that, SES light stays on, see a dealer.
It's got a cop motor, a 440 cubic inch plant, it's got cop tires, cop suspension, cop shocks. It's a model made before catalytic converters so it'll run good on regular gas. What do you say, is it the new Bluesmobile or what?