Giving off code P0206

So my girlfriends jeeps CEL went off today and started running a little rough. I checked it out and it is giving off P0206 cylinder 6 open circuit injector. Excuse my ignorance but would the cylinder 6 be the same as the firing order 6? The 3rd injector from the firewall? Any help is much appreciated!

Assuming you have the inline 6 Cyl motor, they run from front to rear. Not firing order. Cyl 1 is closest to the radiator and cyl 6 is closest to the firewall. And sequential numerical order in between. 1,2,3,4,5,6. The 3rd injector from the firewall would by cyl #4. Swap injectors to see if the problem moves or rent a "noid" light to check the electrical signal to that injector.