In May 2011 went in for fuel pump recall and it appears also had fuel injectors #2, 3 replaced per a different SIB (did not focus on this at the time). In November 2011 (2 mos out of 4 year warranty) experienced engine failsafe message and loss of power. Dealer replaced faulty injectors #4,5,6 as a "goodwill" gesture. Car runs fine now, but just noticed in service records that injector #1 was never replaced. Is this a potential issue? Why didn't they replace all injectors in the first instance?