ultra7350

My blazer has had a rough idle for the past year. I have just replaced the air filter, plug, wires, coil and router. I did a throttle clean also. Good fuel trims, injectors tested OK and no codes with the the tech 2. Still has a rough idle. I have read a service buliton aboutPopit valves sticking when dirty for my type of fuel injection. The next thing I want to do is a injector flush. I know how to do the injector flush but I need to know what to disconnect since it is hard to get to the fuel pump. I pulled the fuel pump relay and the engine still runs. I work with a old GM mechanic and he told me you need to pull the oil sending unit fuse also. Is that correct? If so, where is it?