I have a 2002 BMW 330i, I noticed a problem when I received my car back from my father. He told me he filled my tank with 91 octane gas before giving my car back, I usually put 92 or 93 in. After I got my car back I noticed that the car was idling funny , rough when accelerating and stopping, misfiring, and check engine light came on.I immediately took the car to autozone to get the light checked out. The guy told me there was 14 error codes. They consisted of all 6 cylinders misfiring, large vacuum leak, mass air flow sensor faulty, fuel injector fault, faulty ho2 sensor) he told me that these were probable problems from the codes he received. He told me that I should perform a tune up and that would eliminate a lot of problems , And my father a BMW owner as well said it has too be a sensor if all 6 cylinders are malfunctioning. Before I pay any money to get it fixed, can anyone tell me what could it be out of that list ? And how did this problem occur? Was it because my car is use to 92- 93 octane and he put 91? Or is it just a wear and tear problem. Can anyone shine light on my problem I would greatly appreciate it . Symptoms were: rough idling, jerky when accelerating or stopping , weird turn off, and sometimes when its running it looses power accelerating. The car acts normal sometimes though.