BMW Repair: Fuel consumption - BMW 528i, top tier gasoline, bmw 528i

Question
Tino,

My recentlybought 96 BMW 528i was consuming 16 lt for 100km in city & 10 lt for 100km highway. The spark plugs were bad so I replaced them, changed oil & got the carbon cleaning treatment which is supposed to clean the injectors and the fuel system.

The consumption has improved slightly 14 lt for 100km in city but is still much below what the technical manual says 11.8 lt for 100km in city. Pl. advise what else I can investigate?

Thanks,

Janak.

Answer
Hello Janak,
I guess you have interchanged your city and highway figures.
Mileage can be due to a lot of factors like driving habits,
driving environment, car condition, etc.
But for your purpose, try the following:
a) replace your air filter if it is visibly dirty or not original.
b) make sure that the oil you just poured in is up to specs
(it should be 5-30 synthetic)
c) check your tire pressures and put it approximately 32 psi
front and 35 psi rear
d) use only top tier gasoline (bmw approved gas are available from chevron, 76 and shell); do not use regular gas or alcohol blended gas.
e) check your rpm at idle (it should be from 650 to 750 max).
Try driving the car for some distance and re-check your mpg.
Tell me about it later.
Regards,
Tino