Gas Mileage going down down down

Are calculating by hand or using the truck's computer?
The on-board computers get out of wack after a while and need to be reset via the old battery cable pull trick.

Hi,
Are you taking the winter fuel formulation into account? That will do what you're saying.


Clint

Clint said:

Hi,
Are you taking the winter fuel formulation into account? That will do what you're saying.


Clint

Click to expand...

x2 . . I was thinking that too but don't know where you live.

Two things to know:

Winter fuel sucks for economy.
Your gas may contain a higher % of ethanol than before, which also hurts mpg.

yea ..

Like the guys say ... its winter gas, which I never heard of until I came here, but it totally makes sense. My truck is basically doing the same as yours, loosing mileage. But with all the warming up, and different shifting patterns when the truck is cold .. no wonder ..

not to worry .. spring is coming.
Going to be 10 degrees Celcius this weekend up here in Ontario ... Time to smoke some ribs!!!!!!

d-mo

yep. i was getting 17-18 in the summer, now in the cold winter i'm around 13. i expect it to start heading back up soon.

Have you checked your Air filter??? Just a thought, although some of the new air filters the auto companies put on their vehicles last up to 15k-20k miles, but just to weed out a problem... - that could be just the filter bc they can rob hp annnd fuel economy. like i said just a thought. hopefully if it isyour airfilter that is the source of your problem, that you will NOT just take a compressor with an air hose to it. Instead you need to just buy a NEW one......

Winter fuel combined with the engine idles higher to heat the cats and exhaust faster.
Your also probably idling more to warm the vehicle.

Newer Frontiers really eat gas on a cold start. They have tyhat high rpm when started at "full choke" which really drinks gas and won't go into overdrive at hiway speed until fully warmed up. My 07 Frontier does what yours does.

my wife has actually hit 10 mpg in her X on one tank of fuel.

WandaS said:

The first 6 months I owned this truck (2008 nismo 2x4 v6 quad cab) I got 17.6 mpg every tank. Sometimes more with a combination of city and Freeway driving. Now I'm getting 13,14,15 tops and everything is the same.
The gas, tire pressure, conditions and driving habits.. I'm losing 40 to 50 miles per tank.The truck has 10,000 miles and oil is changed every 3,000.
I'm at a loss to explain this. Has anyone out there had this problem?

Thanks for listening

Click to expand...

Air filter?

Boomer1 said:

Newer Frontiers really eat gas on a cold start. They have tyhat high rpm when started at "full choke" which really drinks gas and won't go into overdrive at hiway speed until fully warmed up. My 07 Frontier does what yours does.

Click to expand...

Yeah my 05 nismo seems to suck fuel on a cold startup, not just for a few minutes, but up until I get in it and start driving it will finally stop, I can tell because of the fuely-fumy smelling exhaust of fuel. After driving on the highway and then back to an idle again, the smell is mostly gone, my truck may be running rich though for reasons unknown, regardless, all winter here in utah I've had about a 18-19mpg hw and 15ish city. Haven't driven it much in the summer yet to compare.

Mine has gone from high 18's to 13's. Never a cold start where I live. Replaced the air filter also, and no increase.

It is cold weather and winter fuel.

I got 18-19 highway during the fall, but 14-15 highway in the winder.

I did fill up with non-ethenal 89 fuel (opposed to 87 with ethenal like i usually have been). I got 17.3 MPG in the winter... i bet this would have been 19 MPG in the summer.

Lastly... it depends on your driving style. Drive too rough, and you'll get a lower than usually MPG.

My truck did this too, but it kept going down tank after tank. a tech i work with suggested running a can of BG 44K through. At $20 a can i figured it was a bunch of bs but went for it anyway. Drove to Sacramento, about a 100 mile trip. Half way through i noticed a major improvement in power, and was amazed when i made it on less than a quarter tank.

I went from 14 mpg city to 17 and from 17 freeway to 23. And it stays there, 3 tanks later. I did this at 80K miles, and i've never touched the fuel system before this.

I just entered this last tank on Fuelly | Share and Compare Your MPG and did 18.2 mpg on a 50/50 hwy/city tank.
There is now 2800 miles on the truck.

Clint