whee.. hooray for bad gas mileage

genericuser

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96 Miata M-Edition, 2015 Mazda 3 Hatch
Not sure what the deal with this is but I have several theories.. I had a tire get a nail in it last week and that caused the last tanks bad mileage.. However, this tank I'm completely confused. Cold weather usually = good mileage. I checked all my tires and they are all sitting at 32psi, the recommended pressure. likewise, I checked my air filter its still looking nice and white and clean. I'm gonna be upgrading to a K&N drop in soon, as I can't afford to get a CP-E.

Alas, I'm confused. I like to limit the use of the rear and front defrosters. I use recirculate for climate control and I usually keep the heat pretty low as cold doesn't bother me much. I don't have any windows open and the sunroof is shut.

Lastly, I keep hearing this struggling gurgling noise from my rear seat. I'm hoping my fuel pump isn't on its way out.
 
welp, so far this tank I just hit the halfway point and I only have about 180 miles on the tank.. usually for a full tank I get about 400+ miles, but I havne't seen above 360 in a while.

this translates to about 25mpg when I normally average 28 at absolute lowest.
 
"oxygenated" fuel?

seanmcsean said:
Not sure what the deal with this is but I have several theories.. I had a tire get a nail in it last week and that caused the last tanks bad mileage.. However, this tank I'm completely confused. Cold weather usually = good mileage. I checked all my tires and they are all sitting at 32psi, the recommended pressure. likewise, I checked my air filter its still looking nice and white and clean. I'm gonna be upgrading to a K&N drop in soon, as I can't afford to get a CP-E.

Alas, I'm confused. I like to limit the use of the rear and front defrosters. I use recirculate for climate control and I usually keep the heat pretty low as cold doesn't bother me much. I don't have any windows open and the sunroof is shut.

Lastly, I keep hearing this struggling gurgling noise from my rear seat. I'm hoping my fuel pump isn't on its way out.
 
Cool weather = good mileage in the spring/fall.
COLD weather = bad mileage in the winter. This happens because the car is programmed to dump more fuel when it's really cold to a) keep the car running, b) warm up the cat, and c) get it up to operating temp sooner. If you make lots of 5-10 minute drives, this will show up significantly with your winter mileage. If you do lots of highway driving it won't be as noticeable... My guess is that your mileage just dropped because it's cold out.

Eric
 
Winter gas mix and idleing to keep warm/defrost the winders usualy is the culprit. Once it gets warm out and winter gas is depleated the mpg should go back up. Just be greatfull you didn't get the atx ;)
 
I dont' really beat on it.. I usually don't rev over 4k rpm.

But yes, I let it warm up in the morning, usually for about 50-60 seconds (usually till the RPMS drop to around 1100 or so) and then I get going. My commute is 30 minutes, so no 5-10 min drives.
 
update: I have a working theory that I'd like to put into place:

first: I have stopped filling up at wawa, and instead, have started going to the sunoco. this has raised my mileage.

second: my commute is just death on mileage.. I thought I did mostly highway driving, but I counted the times I have to stop and start. The traffic lights and stop signs add up after a while. I have a 25 mile commute each way, but on the way home I have to take a different way and there are a lot of starts and stops.. Those add up and give you 25mpg.

after switching gas, and doing mostly highway driving, I achieved an alltime high MPG of 30.21 over the christmas holiday. This was done with about 90% highway driving at around 70mph, and regular road driving around CT at 40-55mph.. It was great when I looked back at the tank and realized that I had put 380 miles on it, and still had a 1/4 tank to go!
 
seanmcsean said:
update: I have a working theory that I'd like to put into place:

first: I have stopped filling up at wawa, and instead, have started going to the sunoco. this has raised my mileage.

second: my commute is just death on mileage.. I thought I did mostly highway driving, but I counted the times I have to stop and start. The traffic lights and stop signs add up after a while. I have a 25 mile commute each way, but on the way home I have to take a different way and there are a lot of starts and stops.. Those add up and give you 25mpg.

after switching gas, and doing mostly highway driving, I achieved an alltime high MPG of 30.21 over the christmas holiday. This was done with about 90% highway driving at around 70mph, and regular road driving around CT at 40-55mph.. It was great when I looked back at the tank and realized that I had put 380 miles on it, and still had a 1/4 tank to go!
So you switched up gas...now try the cheveron additive to see what you get. I personaly run the additive every 3rd tank(don't need to but I do) and fill from only cheveron unless the light comes on in the middle of bumfawk Va. See my reply in next quote for gas milage ;)

ZoomZoomH said:
30mpg...... 380 miles w/ 1/4 tank left....

damn you 4 cyl gas mileage, damn you to heck!!!! (argh)
If it makes you feel any better I just popped off a 368mi range on a remote started, premium fuel only, modded 4.6L 32 valve DOHC pulling a 2 ton vehicle! Now the weather is getting better, that will never happen again.
 
It's good to hear it was only bad gas mileage. I work at a mazda dealership and a lot of the repairs we do on 6's (the dealership has only sold 1 ms6, haven't seen it back for service yet, as i work in the service dept) are on the evap system/fuel pump. ms6's have a different fuel system setup tho and you didn't have a check engine light anyway. :)
 
seanmcsean said:
welp, so far this tank I just hit the halfway point and I only have about 180 miles on the tank.. usually for a full tank I get about 400+ miles, but I havne't seen above 360 in a while.

this translates to about 25mpg when I normally average 28 at absolute lowest.

How are you calculating fuel economy?

Dave
 
same way I always do.. I use the trip counter readout and how much gas I have to refill the tank with.
 
seanmcsean said:
same way I always do.. I use the trip counter readout and how much gas I have to refill the tank with.
Yep I go as far as pumping really slow, stopping at 1st click, and using the same exact pump. 6i usualy get 18.5 usualy around 235 mile range and merc got 23.1 with a 310 range. That auto tranny does bad things to the 6i.
 
Da 6 said:
Yep I go as far as pumping really slow, stopping at 1st click, and using the same exact pump. 6i usualy get 18.5 usualy around 235 mile range and merc got 23.1 with a 310 range. That auto tranny does bad things to the 6i.


I agree i have the 6i with an atx and i am lucky to get 300 in the city. on the highway i can get 400 no problem and that is doing between 75 & 80. I am glad to know that I am not the only one whose car is drinking gas. I fill up on post mostly, cause its always the cheapest.
 
25mpg last tank.. my commute eats gas for some reason.. when I was up in CT I was getting nothing below 28-29
 
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