Ok, one of my cylinders is not functioning properly aka Missing. I have a check engine code of P0174 which is fuel air ratio is lean. The codes also said injector ckt open cylinder 8. So from what i've read on here that injector is just bad and it needs to be replaced? Also the exhaust coming from the drivers side has a very strong gas odor. I haven't gotten out and smelled the passenger side but its definitely not burning a lot of fuel. DO the Coils need to be replaced too? Are there any other possibilities? I've also heard O2 sensors but I doubt the car would drive like one cylinder isn't firing. Thanks for the help.

Oh yeah the car is a 02 mustang gt roush sport vert with only minor bolt on mods. 4.6 2v of course.