Acutualy I had to replace 3 injectors. I took it to the dealership to find there is a GM bulitien out. Apparently the metalic coating that GM used inside the GAS tank came off cloggin mi filter, pump, injectors and so forth. The reoved the entire fuel system and flushed it, and replaced the filters, pump and 3 injectors, recoated the tank with th new coating, and then charged me $860.42 for a GM screw up. Figure that.