Keep your vehicle's fuel system clean with STP Gas Treatment. Powerful cleaning agents in this fuel additive help reduce harmful carbon, gum and varnish deposits that can accumulate over time. Deposits can affect engine performance, and removing the build-up helps maintain engine efficiency and saves gas. A fuel system cleaner like this one is an important step in auto care to help your vehicle run smoothly. This formula also acts as a fuel water remover, helping to prevent fuel lines from freezing. This fuel treatment is safe for any gasoline engine and is compatible with cap‑less gas systems. For over 60 years, and for more miles than anyone can count, STP has been one of the most trusted names in automotive care.