in the dead of night, flooded local auto parts stores for locking gas-tank caps. We sold all our locking gas caps and our gas cans in several hours. in the dead of night, flooded local auto parts stores for locking gas-tank caps. We sold all our locking gas caps and our gas cans in several hours. Ford Mustang and Muscle Car Enthusiast site and forum for Ford Mustang, Mustang GT, Mustang Cobra, Classic Mustang on getting a locking gas cap for my 07 Find Gas Caps & Accessories at JCWhitney.com. Shop JC Whitney for the largest online selection of car parts and accessories.Brief and Straightforward Guide: What are Locking Gas Caps? When gasoline prices rise, so do the sales of locking gas caps.