Fuel system repair involves diagnosing, repairing, and maintaining a vehicle's fuel system, which is responsible for delivering fuel from the fuel tank to the engine. Services may include diagnosing and repairing fuel leaks, replacing fuel filters, inspecting and cleaning fuel injectors, inspecting and replacing fuel hoses and lines, inspecting and replacing fuel pumps, inspecting and replacing fuel pressure regulators, inspecting and replacing fuel tanks, testing fuel pressure and flow, and reprogramming the engine control module (ECM). Additional services may include upgrading the fuel system to improve performance, such as installing high-performance fuel injectors, high-flow fuel pumps, and fuel pressure regulators. Fuel system repairs may be done as part of routine maintenance or to fix issues such as poor engine performance, poor fuel economy, or stalling.