LOL... you were here for all that shitty snow? sucks to be you!

what car do you drive? i think my car is running super rich right now, so that might be why my civic gets such shitty mileage for a 1.6L lol...

haha well... 12L highway is quite insane. i'm making about 11L/100km in the city right now with my civic.. which i find quite odd. is it really windy where you are? just the blazing cold seems to be enough to burn your gas like crazy.

well there's a ton of different factors that could explain it. i believe the mazda 3 is a 2.5L and your is the same? correct me if i'm wrong. i think your car has the higher of the two's curb weights. is yours a v4 or a v6?

things like insufficient tire pressure, lugging around a bunch of crap in your trunk or passenger seats, bad spark plugs/o2 sensors, engine oil that needs to be changed, a clogged air filter, etc could all contribute to the poor fuel efficiency.

the weird thing for me is, my tires are inflated correctly, my rear/trunk is almost completely stripped, engine oil is fresh, air filter/intake is new, and it's a 1.6L!!!

i don't think warming up eats up that much gas to be honest (for my car anyways). it doesn't seem to affect the mileage that much because i warm it up every single day before driving it anywhere.

v4 is so stupid=.= it's such an old design

well think about it. average weight of a passenger (for arguments sake) is 130lbs (if you're driving asians around lol). thats 260 - 520 lbs of dead weight added to your car not even including your weight! you better believe that will use up more gas.

you use the most gas when starting from a stop, thats why city mileage is always a LOT shittier than highway. the weight would only be neglible if you are able to start from a stop only once and don't have to slow down at all. ie, no stopping/slowing down between point A and point B of your trip

you could always try driving NO ONE around and see what your mileage is. you might lose some friends but at least you'll be happier about your fuel usage

where are you getting your numbers from? is it a digital read out on your cluster?

i think it depends on how long you have left your engine off for. if the engine gets cold again, it will eat up more gas until it is up to running temperature. but if you're talking about stopping the engine for literally a few mins, than something isn't right here..

also, if you're going from highway and then into city driving, it does increase your fuel consumption rather quickly.

fun little fact for all the IDLERS out there:

it takes more fuel to run your car for 10 seconds than it does to restart your engine.

you're not saving ANYTHING by idling for more than this time. i really can't understand how people still leave their cars running for 5-15minutes or LONGER at a time.

my guess is that the reading starts off at an average consumption rate. i highly doubt that your car is capable of 9.0L/100km in the city in any circumstance. this would explain the number going up so fast because that 9.0L isn't even close to the real number of 12.5L/100km you ended up at. i hope that makes sense.

keep in mind, my 1.6L uses about 10L/100km in the city or worse; so for your car to be 9.0L/100km would have to mean that your 2.5L is much more efficient than my 1.6L hahah. ie, not possible.

i discovered (from driving a bmw) that it really doesn't matter much if you accelerate at 2000 rpm or less. it's the fact that you have to move a 2000-3400 lb object from a stop that requires you to burn gas.

but anyways, if the 3.5L is a V6 (which i believe it is), it more than likely has some sort of cylinder management system. which means it can switch from 6 cylinders to 4 cylinders to 3 cylinders if it's run at the same speed as you mentioned. it's important to realise that the MPG ratings the manufacturers post are ridiculously unrealistic. they perform these tests in controlled environments under ideal conditions (warm weather, little or no wind, straight roads, no uphills or down) or on a dyno. so logically speaking, a 3.5L engine running on only 3 cylinders can be more efficient than a 2.5L engine using 4 cylinders.

in regards to your cruising rpm's of 1200-1500, try to explain this one: my car is more efficient when i cruise at 2200-2500 than 1500rpm. =)