You can use fuel-injector cleaning chemicals to clear injectors of deposits from fuel and its additives. The products are made with concentrated detergents to break up minerals that form and clog the tiny nozzles on fuel injectors. That reduces the flow of fuel to the engine cylinder, causing hard starts, sputtering and knocks. Automakers have improved injector design, but gasoline quality has declined. Although most major petrol companies add detergents to avoid deposits in fuel systems, injectors can still get clogged.
Find a cleaner with ingredients formulated to work as you desire. Some use lubricants, and many are designed to work on the entire fuel system.
Read and follow label directions regarding how many gallons of gas to mix it with.
Check your fuel level. If your car has a 15-gallon tank and the gauge is at the half mark, you have 7.5 gallons in the tank. Add more fuel if necessary to meet the requirements of the product you're using.
Pour the fuel-injector cleaner into the gas tank. The detergents will clean injectors as you drive.
Consult a certified mechanic if sputtering and knocks do not stop after using a fuel additive. The injectors may need a professional pressure cleaning, or the engine may be experiencing a different problem.
Never add fuel-injector cleaner to a tank with low fuel. The detergent can loosen sediment from the gas tank and the rest of the fuel system, causing a clog in the injectors.