If you are talking about the injector service the dealer throws at you at tune up time then that's an add on, one of several moneymakers they want to add on at tune up time. Traded my '01 in at 81k, traded the '03 GT in at 59k and my wife's '04 PT now has 89k. All three PTs ran excellent and none ever had injector service.
If a person was determined to throw a can of cleaner in there it wouldn't hurt.
