I've had my car for 6 months and am yet to get 400km from a full tank, fuel economy seems to be getting worse. Car has done 108000km so I'm guessing o2 sensors arn't as efficient anymore, just have a few questions. Do the fg xr6t's come with one or two o2 sensors? anyone have part numbers and prices? if car has 2 o2 sensors then do they both have to be replaced? a seller on ebay sent me this message but I have no idea what he is talking about , " One for the inlet manifold which is a genuine part ($185). The other is for the undercooked outlet pipe which is Bosch ($210). " is he talking about the MAP sensor before the throttle body and the o2 sensor before the cat?