Instructions: 1) Pour contents of Fuel Line Cleaner (375 ml) into fuel tank. (TBC200 Cleaner)is only required on engines equipped with throttle body fuel injection or a carburetor and will not harm them. (NOTE: DO NOT USE ORDINARY CARBURETOR CLEANER ON NEWER TEFLON-COATED THROTTLE BODY MODELS AS IT IS CAUSTIC AND CAN DAMAGE THEM) 1) With the engine off, disconnect the air intake boot from the throttle body or remove the air cleaner cover from the carburetor. Spray about half of the contents of the STAGE 4 can into the throat while working the butterfly valve back and forth. Start the engine and spray the remainder of the can contents into the throttle body or carburetor using short spray bursts. Reconnect the air intake boot or air cleaner and let the engine idle for at least five minutes or drive the car at once. NOTE: The "check engine" light may come on due to the rise of hydrocarbon vapors created during the cleaning process. On 1995 and older vehicles not equipped with OBDII coumputers the light will turn off by itself within 5-45 miles, or you may turn it off with a scanner, or simply pull the negative battery terminal for 30 seconds. This is a safe way to reset the coumputer. Keep in mind you will need to re program some accessories such as clocks and radios. Copyright 2000-2010, H.D.I. Management Inc. Nevada, USA all rights reserved. All Logos, Trademarks, & Copyrights are property of their respective owners.