What primary factor can affect the performance of a fuel filter?

The primary factor that can significantly affect the performance of a fuel filter is the level of contamination in the fuel. Fuel filters are designed to trap impurities such as dirt, rust, and other particulate matter that can interfere with the efficient operation of the fuel system. When the fuel is highly contaminated, it puts additional strain on the filter, which can lead to clogging. A clogged filter can reduce fuel flow, leading to poor engine performance and potential damage. Therefore, maintaining clean fuel is crucial for optimal filter performance and overall fuel system health.

While temperature changes, the type of fuel used, and the age of the filter can influence performance to some extent, they do not have the same direct and immediate impact on fuel filter efficiency as the level of contamination does.