Every time you get gas your check engine light comes on why?

If your check engine light comes on every time you get gas, it could be due to a loose or damaged gas cap, which can cause fuel vapors to leak and trigger the warning light. Additionally, the act of refueling might disturb a sensor or an underlying issue in the fuel system. It's advisable to check the gas cap first, and if the light remains on, consult a mechanic to diagnose any potential issues. Ignoring the light could lead to more significant problems down the road.