I've just bought an old 520i Auto and after a week I've noticed that it's giving me really bad mileage, like 8 mpg! There is a little light saying "Inspection" on the dash and the guy I bought it from said the engine was missing a switch. He showed me this little round box, about 3 inches in diameter on the top right-hand side of the engine and said if I get a new switch and plug it in, the light on the dash will go off. Can anyone tell me what the hell that thing is, and does it have anything to do with the low mileage? I'm thinking maybe it's a bad oxygen sensor or a problem with the fuel pump, but I can't find any info on the switch thingy (I sadly don't have an owner's manual).
Any help would be really appreciated.
Any help would be really appreciated.
