When I notice the van running low on petrol (gasoline), I attempt to secretly refill the tank so that Cathy is frequently surprised with a full tank of gas. Yesterday she found herself stranded at the mall because the van refused to start. She claims she was out in the cold for an hour and a half. I arrived and after some futzing with the van the engine roared albeit roughly and with a warning light. Eventually we found our way to Autozone whose computer reported that the MAF/MAP sensor was overloaded. Great, sensor replacement time. Wait a minute! Hadn’t seen this before? Oh… yes. I walked out the door to the van, removed the gas cap, and replaced the gas cap, the warning light faded away, and the engine ran smooth. See, in modern vehicles, the fuel system is often pressurized so if the gas cap is not sealed well, like it’s crooked, then the engine has problems getting fuel.
n.b. The gas fairy does indeed sound like a walrus.
Tl;dr The van wouldn’t start leaving Cathy was stuck in the cold for an hour and a half because I put the gas cap on crooked.