These are new OE injectors-not aftermarket will fits or rebuilt. They are the same as what originally was installed in the engine when the vehicle came off the assembly line. These injectors can be identified by the "AD" code on the injector solenoid. Alliant Power is the exclusive supplier of brand-new, genuine original equipment, HEUI fuel injectors for 99-03 T444E ESN 843990-5999999 WARRANTY: Alliant Power injectors are warranted for 13 months/unlimited miles. The warranty period commences the day the product is delivered to the original consumer/purchaser. Alliant Power warrants that it will replace, free of charge, any product which, under normal conditions of use and service, proves to be defective in material or workmanship and is within the warranty period. A core charge of $250.00 will be applied to your credit card account, if the core is returned within 30 days you will receive credit. Feel free to call our parts department at 800-891-8038 with any questions.