[bmwhitman]

I\'m getting 16 to 18 liters per 100 km
for mostly city driving . Is that excessively high?

[Glim]

Originally Posted by bmwhitman

I\'m getting 16 to 18 liters per 100 km
for mostly city driving . Is that excessively high?

For an M3, no

For my 2006 330i I use 13.1 liters per 100km city.

[bmwhitman]

Agreed, but mine is not an M3, it's a 330i. I noticed this after changing from BMW 5w30 oil to GC Castrol 0w30. Also, I just recently changed my air filter and new spark plugs from the original plugs to the BOSCH OEM's. I know it's getting colder in Toronto but I use to get 12-13 litres/100km. Still boggles my mind.

[Glim]

Wow

I would put the original plugs back in and see if it changes back.

Did you use antisieze? If so the plugs may not be grounding properly. Not sure if that would cause such a dramatic increase of fuel.

[Clifton]

Retrace your steps. I'm with Glim, the new plugs sound suspect. Are you certain they are the exact plug for your car? Lots of plugs will work, but I'd stick to BMW branded plugs, even if BOSH makes them for BMW. Sometimes there is a difference.

[bmwhitman]

Yeah I'm suspecting it might be my plugs. Just a pain to pain to get them redone though but I might have to go that route.

[Glim]

Does not take that long, hardest part is waiting for the block to cool.