"If the consumer notices right after filling up with gas that there’s a drivability problem, the service check engine light comes on or vehicle is stalling, it's possible they dispensed contaminated fuel into their tank,” Jay Garbe, Weights and Measures Petroleum System Supervisor with the Wisconsin Department of Agriculture, Trade and Consumer Protection said.
In addition to making sure the proper type of fuel is being dispensed out of each pump, inspectors test to make sure the fuel tanks aren’t contaminated with water which can cause problems once inside your gas tank.