What is a common effect of fuel contamination?

Fuel contamination typically leads to the clogging of filters. This occurs because contaminants—such as dirt, water, or microbial growth—can increase the viscosity of the fuel and introduce particulates that obstruct the flow through fuel lines and filters. When filters become clogged, they hinder the fuel system’s ability to deliver an adequate supply of fuel to the engine. This can result in reduced engine performance, difficulties in starting, and potential damage to the fuel system components.

Other choices do not represent common effects of fuel contamination. For example, improved fuel efficiency and longer fuel shelf life would not be associated with contaminants, as they tend to degrade fuel quality rather than enhance it. Similarly, while increased air emissions might occur in some contexts, it is not a direct and inevitable result of fuel contamination in the way that clogged filters are.