Restore factory fuel delivery, smooth idle quality, and dependable performance on your 2006-2007 GM 6.6L Duramax LBZ with this genuine Bosch OE remanufactured common rail fuel injector. This direct-replacement injector helps correct injector-related concerns such as hard starting, rough idle, excessive smoke, fuel knock, poor throttle response, balance rate issues, reduced power, and drivability concerns under load. Bosch: 0986435521, 0 986 435 521 Installation Note: Always use new seals, lines, and installation hardware required by the service procedure. Fitment Note: Verify build date, VIN, engine application, and existing injector part number before ordering. Core Charge Notice: Core return required. A refundable core deposit will be applied at checkout and refunded after receipt and approval of a rebuildable core.