The primary reason why gas won't ignite is due to a lack of a proper flame or spark. This can be caused by several factors, including a clogged fuel filter, a malfunctioning spark plug, or a depleted fuel supply. Additionally, issues with the air-fuel mixture, such as being too rich or too lean, can prevent combustion. For instance, according to the National Institute for Automotive Service Excellence (ASE), a spark plug that is not functioning correctly can result in a misfire, leading to a failure to ignite the gas.

In the United States, the issue of gas not igniting is a common concern among vehicle owners. The ASE reports that spark plug problems are one of the most frequent causes of engine misfires, accounting for approximately 21% of all engine performance issues. A study by the Automotive Service Councils of America (ASCA) found that a significant number of vehicles have spark plugs that are either worn out or not properly gapped, which can lead to a failure to ignite the fuel.

The air-fuel mixture is another critical factor. If the mixture is too rich, meaning there is an excess of fuel relative to the air, the engine may not ignite properly. Conversely, if the mixture is too lean, with too much air and not enough fuel, the engine may also struggle to ignite. The Society of Automotive Engineers (SAE) notes that the ideal air-fuel ratio for most gasoline engines is between 12.5:1 and 14.7:1. Deviations from this ratio can lead to ignition problems.

Furthermore, a clogged fuel filter can restrict the flow of fuel to the engine, preventing combustion. The National Highway Traffic Safety Administration (NHTSA) has reported that a clogged fuel filter can cause a decrease in engine performance and, in some cases, a complete failure to start the vehicle.

In summary, the failure to ignite gas in a vehicle can be attributed to issues with the spark plug, air-fuel mixture, or fuel filter. These problems are well-documented in various studies and reports by automotive industry organizations, highlighting the importance of regular maintenance and timely repairs to ensure proper engine operation.