I'm usually on the 720 forum but started reading up on other forums. Need some help with the fuel consumption on my 2000 Wingroad. Its the same engine and suspension platform as a B15 and lately the fuel consumption has gone from 365 miles per tank to 300. It carries a 12 gallon tank. I've never done a fuel system clean since I bought the car in 2006 but add a fuel system cleaner every 3 top ups. Could this also be because of the oxygen sensor?

yes. a bad 02 sensor could have her running rich, inturn burning more gas

Thanks for the help.

Instead of using the regular stuff try using the STP in the silver bottle. It will clean your fuel system out alot better for only $5

Used a product here called QMI. Exhaust has cleaned up, gets better gas milage but still a little sluggish under power. I'm not ecstatic but very happy as a new sensor costs $US 230 and the treatment costed $US 3.25.