GM puts 6 different injectors in the new gas engines. The rails are assembled at the manufacturer. The difference between the 6 types is flow. GM them just slaps them in an engine.
So last week, needed to replace a leaking one.
Pulled it out, took it to parts, they looked at numbers on it and gave me a new one.
Fast forward to today, its back, check engine light and fuel trim codes.
After much banging my head against the wall, parts gave me the wrong injector.
I restrained myself from choking mf'ers out, but I told 1 of them to bend over, jam his head up his azz and keep shoving until he gets his entire self up his own *a-hole.