Abnormally Terrible Gas Mileage

Been a member since I bought my Tacoma last November but this is my first post because I'm a tad lost.

For the last 3 tanks now my fuel consumption has been terrible compared to previous tanks. I'm getting 25 liters per 100kms. Roughly 300kms per tank and that's just not good.

Within the last month to two months I was bringing her up to speed; New iridium plugs, oil change with AMS (along with both diffs and transfer case), and a new drop in k&n air filter. Tire pressure is fine, no check engine light, so what do I do next? O2 sensor? Purge the injectors? Fuel pressure?

Appreciate any info or tips

 

Oh and that's my Tacoma.
2009 TRD

 

Go to the top of the page. Click on mods/tutorials then go to improve gas mileage

 

What brand and model plugs

Also what gap did you set them to?

The K&N filter is useless to put it nicely. If it was over coated with oil it can contaminate your MAF and would need to be cleaned.

 

OP, do you have fill-up receipts with what the odometer was at when you went to the pump? For those in the USA... OP is reporting 9.5mpg which I've never heard of. Really doubting the math. Open up a fuelly account (banner below) as I find it's the best way to accurately track fuel usage.

Like others have said, stock air filter is probably the best medium you'll get. Spending more money on more expensive filters is just a waste of cash. Also don't rely on the TPMS and check your tire pressure with a gauge to be sure they aren't running low (could be low just not low enough to set off the warning). How fast are you driving? Going over 105kph you really start to see a decline in economy.

 

Thanks guys.

NGK iridium plugs
How would one clean the MAF sensor?

As for speed, all city driving, 50- 80 kms an hour.
I went to fill the tires up the other day, used a gauge, they were perfect.

I was thinking about filling up the tank, driving 100kms and then filling up again to see exactly how many liters I used. Thought maybe the truck isn't giving me the right reading of my mileage.

I'll look into opening one of those accounts too.

 

Your mileage would be correct, but the fuel gauge is just an estimate and useless for determining fuel economy. If you don't go the fuelly.com route:

1. Fill up your tank, write down the current odometer on the receipt/paper. Don't top off the tank, just fill-up and let the pump auto shut-off.
2. Next time you fill-up write down how many litres pumped and current odometer.
3. Calculate L/100km (#litres/#km)*100
4. Repeat 2. and 3. for 3x fill-ups (full tank, no top off) and see how you fair.

 

Cold weather is one cause.
Has your gas stations recently switched to 10% ethanol? Ethanol is bad for mileage and power.

 

Has the power backed off? Could your CAT Converter be plugged?

 

Get rid of the KN filter and stick with stock filter for air. The plugs should be those recommended by Toyota.

 

pretty sure all 87-92 oct in Canada contains 10% ethanol, only chevron 94 is contaminant free!!!

also its Vancouver it don't get cold it just rains lol

If your're not throwing any codes I'd check to see if your cat is plugged being emissions exempt means a lot of newer cars don't have those systems checked often. like previously mentioned if you're way down on power thats probably the reason!!!

 

If you are correct at 9MPG you got a leak some where!

 

You driving in too low of a gear, that is in 4 and not D?

 

How can you tell if your cat converter is plugged? or how can you unplug it?

 

I do switch from 4 to D in the city. I just figured with Vancouver being so hilly that cruising at 30 - 50 kms an hour in D puts too much strain on the vehicle.

 

Shell V Power 91 is still ethanol free in Canada

 

FAQs

Shell V-Power premium gasoline in Canada does not contain ethanol.

http://www.shell.ca/en/products-services/on-the-road/fuels/shell-vpower.html

 

It might not be practical with EFI. I don't know what codes your truck will throw, or how it would run. But there is a thing called a "test pipe" that you can install temporarily in place of the cat to see if it is better without it. But I simply haven't used one since about 1978, honestly. If it were me, I'd find an honest muffler shop and tell them my symptoms. Maybe they have a way to test it, or at best can steer you in the direction of a cheaper replacement. If it is the cat, it can not be "unclogged". It can be hollowed out, but, you don't want to do that.