My girlfriend has an 03 cts 3.2 ls, it has had a misfire for a while so I decided to take it up to the local parts store and have the cel codes ran and it had the p0300 multiple misfire, p0303 cyl 3 misfire and the p0305 cyl 5 misfire, so went out and bought the coil pack for that side changed and still throwing the same code so thought it might have Been the plugs so changed them and still has the misfire.. Was wondering could it be the injectors?.. I know very little about caddys so kinda going into this blind so any help will be greatly appreciated