Gas mileage getting worse by the tank

[BurningRubber]

Its gone from about 290-310 or so to the tank down to about 255-265 or so. Driving habits havnt changed.

Plugs (coppers) and fuel filter have right under 10k on them, I also replaced the boots and coils on the COP's, and it was still getting the normal range for a while after that. Just recently it has dropped. Been using multiple stations to so I dont think its bad gas.

 

[Kilgore Trout]

Cars get worse mileage in the winter time.

 

[Kurgan]

Change your fuel filter lately?

And yes the change in fuel mixtures during the winter (government mandated in many states) can negatively affect fuel economy. Not to mention the gas is a little more expensive.

 

[Kilgore Trout]

To accurately measure mileage you must not only go to the same station every time, you must use the same pump. You must be meticulous in your record keeping. Your variance in mileage could be mostly due to inaccuracies in your technique. Google for tips on accurately measuring mileage.

 

[BurningRubber]

Fuel filter has around 10k on it.

I didnt think about the different gas blends now, I always thought the summer blend was worse though. I think I have it backwards.

 

[Skidzz]

Cars get worse mileage in the winter time.

+1

There is also a chance that it could be A/F ratio related. You might want to check your air filter (if you haven't already, but I'm assuming you already have). You never know though. If it's not a DRAMATIC drop, then it's probably just due to the seasonal change.

 

[Evenflow]

Jeez im lucky to get 200 to the tank.

 

[Skidzz]

Jeez im lucky to get 200 to the tank.

That seems strange. I get about 300. 200 seems pretty low.

 

[BurningRubber]

Jeez im lucky to get 200 to the tank.

Good lord mang, how?!?!

You drive WOT all the time or something? lol.





My K&N could use a cleaning.

 

[2oo3gt]

I get about 230. Its really ****ty. And i drive conservitivley.

 

[whyask]

Ya I get around 190-210 city.....I LOVE MY 4:10's and straight pipes

 

[Ram5773]

Mine dropped off from 250 260 down to about 210 to 200 with no change in gas or driving habits. What would they change in the mixture of the gas?

 

[stangGT97]

I get about 230. Its really ****ty. And i drive conservitivley.

yeah mine is around that range too. Well usually I get about 19mpg with a mix of highway and city but I hardly ever go WOT so I would think it would be better..

 

[02TruBlueGt]

I get around 230-250 driving softly. I wish i could get 300 lol. Going to get even worse after my 4.10's go in . Aww well gotta pay to play hehe that inlcudes gas.. haha Yea all cars get worse mileage in winter like they have been sayin.

 

[Ram5773]

Do you think the mix changes for the guys down in the southern states?

 

[03ghoststang]

even with 4.10 gears on i get about 250-270mpg but i dont really care much for it

 

[Kurgan]

Something else I thought of..

If your fuel pressure sensor (on your fuel rail) is not reading properly, the PCM will increase the fuel pump duty cycle increasing pressure in your fuel rails, which causes your injectors to spray more fuel than they should. You can get a dealer or tuner to read the fuel pressure readings from the PCM using a scanning tool or OBDII datalogging tool. If this happens to be the case, simply replacing the sensor would fix the problem.

Check out this article for some diagnostic tips:

http://www.aa1car.com/library/returnless_efi.htm

 

[jstreet0204]

Winter formulated gas has a slightly lower stoich point (14.4:1 ~ 14.3:1) so the car will run richer in closed loop. Add to that the fact that in cold weather, the eec uses cold startup tables (which are programmed richer), for a longer period of time. We also tend to let our cars warm up longer when its cold, the car does not reach the same operating temp when it is cold, etc...

Put all that together, and basically winter = lower fuel economy.

 

[04GTMustang]

hahahaha i would also love to get 300 to a tank, i do on the highway even with the 3.73s. my around town mileage lol i get about 180-200 lol, and yes i drive it hard. ever since i got those 3.73s my foot seems to love the floor board more and more.

there fixed

 

[04GTMustang]

man i just read my previous post lol talk about a run on sentence let me fix that.