Fuel injectors directly affect the air/fuel ratio for the engine and new fuel injectors do require a new or updated tune. We also suggest that you check the other component of the engine before installation. No special tools are required. It is easy to replace old fuel injectors. Each fuel injector has a protective cap that must be removed before use. Car Petrol Injection Nozzles CDH210 0280155723 INP-771 MD319791 for Chrysler for Sebring 4Pcs Set Fuel Injection Nozzle The injector's unique nozzle design reduces fuel injection noise and enhances cabin quietness. Its reinforced structure provides vibration , stable spray even on bumpy roads and adapting to various engine modifications. The injectors are manually replaceable and made of high-strength, waterproof, and durable material. They directly replace faulty injectors with high reliability, efficient and rapid fuel , shortening vehicle starting times., Manufacturer: ZXCTQQS