I have just imported a vezel X 2014. It's a self import and 4.5 grade. However when I got it delivered there is a kind of engine noise when the car goes to petrol. Everything else is super fine, just the noise. The car is not tampered with and since it's 4.5 grade I'm wondering why is there this noise, my importer is saying that it's because at the port they had to put Irani petrol and that I should fill the tank with octane and soon the noise will go, so my question is that is it normal or should I be worried. I showed it to a mechanic and he said not to worry and the noise will go away but he was a conventional mechanic. Any suggestions will be welcome. Also I I have gathers TV Navi system, it's showing security code error, how can I find the security code, there is also a USB with a SD card that says internavi what should I do with it.
In addition to this would welcome some starter tips for vezel.