Ok, I own a 2009 BMW 335i with an N54 engine
and automatic transmission, 42k miles. Car was purchased new. The car had the injectors replaced 2 months ago (the old injectors were making noise and the transmission was rough) and initially was driving great, it was like having an extra 40 more HP. Had the car in service at the same BMW dealership for an unrelated issue 2 weeks after, an IBS error code . They kept the car for 2 weeks and found nothing. But when I got the car back it was like they would had swapped the new injectors with the old index 7 defective injectors. They put ~ 70 test driving miles on my car and the gearbox issues were back. I brought the car back but they claim there are no issues with the car. There is a way to check if my car still has the new injectors or not. There is a trace left ( of new injectors being programmed ) on car's DME for example. How can I check if these are indeed 2 moth old injectors?
JA: Have you heard this particular sound before?
Customer: no more injector ticking sound as before. And no more white smoke. But the car lost some of the newly "aquired" power and the transmission shifts rough again ( occasional jolts, rough shift from 2-1 especially when the engine is hot)
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: I suspect they might have put some used injectors into my engine but I need to make sure this is what happened. I can take the car to a different BMW dealership if needed. Actually I don't know what to do at this point
JA: Anything else you think the mechanic should know?
Customer: Yes. This dealership "forgot" to give me an invoice following the injectors replacement. I had to insist to get one. On the Invoice I finally got they mentioned they replaced "index 7" injectors that were defective. I don't understand how my car had index 7 injectors, these have been discontinued 1 year prior my car being built (July 2009) This is another strange fact...