I had the same thing happen to me this month. 2005 V6. Turned the gas cap 5 clicks, solved the problem. I ordered a new OEM cap and will replace when it gets here.
Bought it in Oct of this year. 2005 Sport 4x4. 105k. Super clean minus a few scratches on the bumpers. All fluids done and brand new tires, alignment, etc... 13,8k private party.
Side note: was looking at a dealer when a 2001 Limited w/78k was being traded. Sold for 13.9k before the trade was...