What's wrong with this picture? (18 MPG, 40k miles)
 

I've been driving my '08 Fit for about a year now, and I love the car. I delivered pizzas last summer and it treated me perfectly, the mileage was great as I was on the highway most of the time, and life was swell. However, things have taken a turn for the worse as since then (about a year ago) my MPG has been absolutely terrible. I usually have to fill up about once a week, and my average mileage per tank is around 18 or so. Needless to say, terrible for a Fit or any other car.

Some info:

• I'm a high school student
• I try to keep my RPM around 3000-4000, I rarely gun it to show off, as showing off in the Fit is a relative term
• I live in a tiny (one square mile) town, and as such I drive very limited trips.
• I start my car 7-8 times a day, not sure if that applies, but anyway.
• Maintenance is always taken care of, as my father used to work on cars, and knows what he's doing. Regular things (oil, rotations, what have you) are not being neglected.

So really, this MPG is either my fault, or there's something I haven't thought of. Any ideas?

What transmission do you have? Manual or auto?

Keeping your revs below 3400 RPMs, anything above VTEC will engage and you will use more fuel. I personally shift between 2500 to 3000 RPMs to save fuel when there is no traffic, 2800-3400 when there is.

Also, make sure your tires are inflated properly, engine air filter is reasonably clean, get rid of any excess weight from unneeded items being in the car, and of course use a quality fuel.

I drive an automatic. As for air tire, I had some issues with one of my tires having a slow leak but got that fixed a few months ago, and check the tire pressure regularly. Usually the only thing in my car is me, my iphone, and some running shoes.

Missed the engine air filter question. I've been wondering that myself, but don't have the knowledge to check it out; is it really as easy as those youtube vids make it look?

When you turn on the fan blower to suck in fresh air or heating, ensure that your dial is NOT on the position of windshield or windshield/feet. W

Windshield or windshield/feet position will activate the defogger function and switches on the A/C without you pressing the A/C button and without you knowing it. A/C condenser pull on your engine kills MPG

The Fit has a small engine, and if you drive it aggressively, the engine will be working very hard in order to keep up. I have averaged low 20s on my friend's 09 Fit when driving with a lead foot in flat terrain, so it is definitely possible that your fuel economy is normal.

first off, let me say this: your car is an 08... so it really belongs in the 1st gen section. because Hootie's point about the 3500 rpm VTEC engagement will surely confuse GE8 newcomers. yes, I understand that the section title has "08"... the problem is... that 08 only applies to JDM because they got the GE model one year before us. the 08 in the USA is still a GD.... the GEs have VTC and VTEC... VTC engages different stages at different RPMs, with VTEC engaging at 5400 rpm. I'm in a few (heated) topics about it.

I start my car twice as much as you do. And while it does affect MPGs... I'm thinking it's other things.

When you drive... how consistent is your foot? the more you move your foot... the more gas you're gonna end up using.

when you know you have to come to a stop (sign/red light)... lift off the gas early and let it coast to the sign, usually it'll also slow itself down (its going to engine brake itself)... then gently apply the brakes so you come to a full stop near where you should stop.

being that the town is 1 sq mile, it might not have a gas station that cycles it gas quickly enough. there's a topic about that too (but I'm not in it). the longer gas sits in a tank... the more it will differ from "fresher" gas (additives separating, degrading, etc).

You've been driving it for a year? Being that its an 08, does that mean it was bought used? has your father or any other mechanic taken a look at the engine? There could be all kinds of crap going on if the previous owner mistreated the car and just "cleaned" it up long enough for someone to buy it.

Sorry, being a newcomer I couldn't figure out which was which subforum. As for the gas station, I wouldn't assume it doens't cycle gas quickly enough, although it's only one square mile it's a very populated area. It was not bought used, my brother had driven it before I did, so it had always been in our hands.

I'll take a look at how consistent my foot is, I never really took a look at that, and while a lot of the time I'm coasting, I never really pay attention to my pressure on the pedals.

Wasn't aware of that. However, if I need to use the heat on the windshield position, is there any way of avoiding the problem? It's not that feasible (as far as I know) to not use the windshield heat sometimes.

You keep your RPM over 3000 most of the time? I can't compare because I have an AT but isn't that kind of high when you're not accelerating? Even on a highway going pretty fast I think my RPM is below 3000.

That said, if you take it back on the highway is the mileage the same as it was when you were happy with the car? Or has something changed? Maybe the air filter is clogged or your A/C is stuck on or your handbrake cable froze so even when the handle's lowered your engine is fighting the brakes...

Or maybe you never drive more than a mile at a time so the car never warms up. I don't know how big an effect that has on fuel consumption but it has some effect.

Oh, do you spend any time sitting still? Waiting for people to come outside, or listening to the radio with the car idling? Or letting it warm up for any amount of time when you start it? All waste fuel.

are you still running the stock spark plugs?

i would check your air filter asap. keep your rpm under 3500 for a tank of gas to see what your mpg will become.

I realized after I posted that I meant that was when accelerating, it's generally around 2000. On the highway, the mileage is pretty close to what I used to get, and I can get around 28-30 (I know it's not perfect), but I like it. I usually drive 3-4 miles at a time, but I'm not sure about the heating up, I assume that could be an issue. As far as idling, I don't idle very much, unless in a rare circumstance someone is running in to get something, so I don't know.

I'm not sure about the spark plugs, how is that checked? I plan to check the air filter as soon as I get out of bed. :)

Just to be sure- you check your tire pressure before you've driven the car anywhere that day, right? Not after driving.

I just went out and checked the air filter:
Putting links because pictures weren't working.
http://img535.imageshack.us/i/img0208nx.jpg/
http://img222.imageshack.us/i/img0209lv.jpg/
http://img832.imageshack.us/i/img0210cu.jpg/


While I was there, I checked the air pressure, and from top right going clockwise the pressures were: 32, 30, 30, 30 (PSI) while the "optimal"? is 32, so if that's a big deal I can put more air in.

its all the short trips. problem solved.

A couple of lbs under wouldn't make a huge difference but it wouldn't hurt to inflate a lb or two more than the 32 if you're making all short trips.

I had feared someone would say this. But at the same time, friends of mine making nearly the same trips get better gas mileage in cars that should not be.

If I drive for short trips my mpg is about the same.

just a thought but inflate your tires to 40psi for a few days to see what your mpg will be.

its not something to run everyday but the guys on some eco friendly forums recommend higher tire pressure for less rolling resistance but your tires will wear quicker.

many hills localy? thats the only thing that kills my MPG