I have the same model, driving it in Norway. I know there are certain differeces between the european models and the models sold for the american and canadian market. Anyway, I suppose you have the B230F-engine, as I have in my GL, and this engine is an injection engine with katalysator using the Lambda sond (oksygen sond) to blend the fuel/air.

I recently checked with a workshop if they could do something with my rather high fuel consumption (1.3L per 10km., driving in city), and they responded the only thing they could check was the Lambda sond: This device adjust the blend to fit the katalysator. Else, I should check the air intake filter and the spark plugs.

My reccomendation for you is to get yourself a Haynes repair-book for your model, and study the exhaust-conditioning system of the car. There are among others a charcoal-filter which maube could contribute to your problems.

While I'm at it; which fuel quality are you giveing the puppy? 91 octane? That's the lowest recommended quality over here, but we only have 95 and 98, so I run mine on 95. The rumors of the jungle says that you occasionally should even run these engines on a full tank of 98, just to clear things up...