Contaminated fuel can severely impact diesel engine performance, affecting emissions and overall efficiency. Common causes of dirty fuel include poor fuel quality, water contamination, particulate matter, sediment buildup, incomplete combustion, fuel additives, storage and handling issues, cross-contamination, and aging and oxidation. Dirty fuel can lead to sluggish acceleration, rough idling, reduced power output, and increased emissions. Over time, contaminants can cause wear within engine components, especially fuel injectors. CNH Reman emphasizes the environmental impact of using dirty fuel, which can elevate pollutant emissions. Recognizing symptoms of dirty fuel early on, such as reduced power, rough idling, and increased emissions, is crucial. Proper fuel management practices can ensure engine longevity and environmental health.