Help! I have a 2005 Honda Element EX AWD with 92000 miles that I've owned since it had 5000 miles. Over the years I've consistently got 22-27mpg (27 on highway trips). Over the last 6 months or so my mileage has sucked. I barely get 220-230 miles per tank, even with highway driving. This has been something that I've been consistently tracking. I drive very easily, I never push it hard or drive aggressive. My driving habits haven't changed. I keep up on my maintenance. Nothing seems to be wrong. What might the culprit be??? I'm ready to sell the thing with such bad mileage but I love my E.

> I keep up on my maintenance
At 92K miles, does that include new spark plugs and a valve adjustment? Your air filter is recently changed, and no critters nesting there? Tire pressure is at spec?

No performance/driveability problems?

> 220-230 miles per tank
Just to be clear, you are calculating miles per gallon according to the accepted method, yes?

Welcome to winter. After you run outside to start the car to let it warm up, it's getting exactly 0 mpg. Then cold, denser winter air doesn't help either. You're making more power believe it or not, but you're also burning more fuel to keep the air/fuel ratio where it's safe.

Cold winter air packs more oxygen molecules per cubic foot than nice warm 85 degree summer air. To make for the increase in oxygen, the computer adds more fuel. No way around it.

> I keep up on my maintenance
At 92K miles, does that include new spark plugs and a valve adjustment? Your air filter is recently changed, and no critters nesting there? Tire pressure is at spec?

No performance/driveability problems?

> 220-230 miles per tank
Just to be clear, you are calculating miles per gallon according to the accepted method, yes?

I'm going to go change the spark plugs today... other than that everything looks good. I saw someone talking about the gauge you can by that tells you your mpg in real time. I might pony up and buy that.

Welcome to winter. After you run outside to start the car to let it warm up, it's getting exactly 0 mpg. Then cold, denser winter air doesn't help either. You're making more power believe it or not, but you're also burning more fuel to keep the air/fuel ratio where it's safe.

Cold winter air packs more oxygen molecules per cubic foot than nice warm 85 degree summer air. To make for the increase in oxygen, the computer adds more fuel. No way around it.

My winter mpg has always been lower but never this low... I'll try letting it warm up more and see what happens. Thanks!

You missed my point. When it's sitting there idling to warm up for 10 minutes or whatever, it's burning gas, but getting 0 mpg. Your average mpg will go down because of this.
In the winter I autostart mine and don't care about mileage. I care about me being warm when I get in.

I saw someone talking about the gauge you can by that tells you your mpg in real time. I might pony up and buy that.

What gauge? You talking about a $200 scan gauge? You know how much gas you can buy for $200?

My mileage has always ranged from 18-23, but my last several tanks have been under 18...I know it's because of the cold weather (and crummy oxygenated fuels in CA) but there is a psychological difference to me between 20 and 17. I can't help but feel like a Suburban wouldn't return much less mpg than my element sometimes...

At 92k DO NOT overlook the valve adjustment.

. . . Cold winter air packs more oxygen molecules per cubic foot than nice warm 85 degree summer air. To make for the increase in oxygen, the computer adds more fuel. No way around it.

Really?

I thought that O molecules /fuel molecules= C, and RPM was proportional to the fuel burned, so if the fuel burned caused an increase in rpm, the ECM would decrease the air volume pulled through the throttle downward to compensate for any increased air density.

The decrease in fuel efficiency as temperature drops comes from heat(energy) lost as thermal radiation, that needed to overcome the increased fluid viscosity, that needed to raise the operating temperatures of fluids to optimal efficiency and that used to warm the cabin. All that energy coming from the fuel combustion isn't available to push the pistons, so more more fuel has to be burned to make up for the lost energy.

Another temperature efficiency loss comes from the drop in air volume in the tires with temperature, roughly 1 psi/10 degrees C. That increases the rolling friction of the tires, increasing the net wasted energy.

"Wind chill", a measure of heat loss due to air motion equivalent to a lower than ambient temperature, is a good indicator of wasted energy. Any increase in relative air velocity causes a heat loss that is non-linear and becomes more so as the temperature is lowered.

I adjust my tire pressure weekly, based on the average predicted daytime temperature for the next week. My E's fuel efficiency has dropped by 10% since its high last August.

You missed my point. When it's sitting there idling to warm up for 10 minutes or whatever, it's burning gas, but getting 0 mpg. Your average mpg will go down because of this. In the winter I autostart mine and don't care about mileage. I care about me being warm when I get in.

I also let m E idle longer before driving in the winter - 20 seconds instead of 10.

I'd rather spend some money on durable clothing than on ephemeral fuel; it's cheaper. If you dress for the environment, in the winter you'll feel warmer in an unheated closed vehicle than outside (the wind chill is lower), and you can lower reduce the cabin fan speed and/or heater level. :-)

At 92k DO NOT overlook the valve adjustment.

. . . or any of the suggested or scheduled maintenance. A well-maintained vehicle is an efficient vehicle.

Really?

Yep, really.

So I changed the air filter and put in new spark plugs... still 16mpg. I just installed a ScanGauge this morning, after using it my cars idle was erratic. Anyone experience this? I guess next steps are a valve adjustment.

Installed a ScanGauge... it's actually been really great to figure out my driving habits and how they relate to my mpg. Some things I've learned:

Don't be so timid when accelerating... you get worse gas mileage by accelerating too slowly... seriously. Same thing applies when going up hills. I was driving around like a grandpa thinking it was helping my mpg. From everything I've tested it's been hurting it. Now that doesn't mean drive like a race car driver but there's no need to be timid.

Head wind kills your mpg. Bad.

City driving kills your mpg.

Coasting and coasting to stops give you a big boost.

Going up a hill and then going back down it does not equal out your mpg. You actually get really good mpg. I get about 7mpg going up a hill but 55 mpg coming down... 33mpg average. I always wondered why I got great gas mileage driving to Park City. Now I know, the way down gives you a huge boost.