Hi friends . I want to share a problem im facing in my crown 2003 2jz fse. I changed its oil 1600 kms ago. Yestarday i checked its all black . I use mobil 1 5w-50 in it. Oil is prefectly complete at the dot of the stick. Wht can be the problem ? Pick up is slightly less than before. Plugs have become brown on 10000 kms. Wht can be the issue ?? Fuel ? Vaccum sensor ? Or something else ?