2. What should you do to the engine to help keep injectors and combustion chambers clean and free from stale fuel and carbon deposits?
A. Run engine with Marvel Mystery Oil.
B. Run engine with Dawn dish-washing detergent.
C. Nothing; you will harm the engine by injecting anything but regular fuel.
D. Inject most of a can of Engine Tuner, Power Tune, Sea Foam or equivalent into the engine's intakes while running the engine at a fast-idle speed. Shut down the engine, wait overnight, then start the engine again and inject the rest of the can into the intakes.