[gfayez]

When I try to accelerate slightly on low rpm I hear valve knocking, if I take my foot off the accelerator and then push again it disappears. If I’m in sports mode this never happens. To give you a brief history I suffered an drivetrain error and the dealer said the error code was turbo overheat because there was a leak in the turbo cooler radiator and it was replaced, and once again I had drivetrain error and dealer said it was a misfire in cylinders 5&8, and then he came back with a stupid saying that it was because unburnt fuel particles in the cylinders and that I have to every now and then run the engine hard. This sounded to me like a load of crap. I use fuel octane 95 and my engine is v8 4.4 twin turbo 450hp. Any idea what is causing this