A tool for removing an injector sleeve from the cylinder head of a diesel engine between the rocker arms while the head remains mounted to the engine block within the vehicle. The devices includes a tap having a longitudinal body and a thread cutting head at one end. A drive member comprises a bolt having a head at one distal end. An extraction nut is threaded onto the threaded shaft of the drive member followed by a bearing surface member such as a spacer. A hollow cylinder or support sleeve having an internal diameter greater than the injector sleeve to be removed and an external diameter less than the diameter of the sleeve bore includes a shoulder member.