Well, already my Lancer got bad gas mileage like im guessing 20 to the gallon?
But now all of a sudden out of no where seems that its gettin worse, I don't need an oil change, and dirty air filter wouldnt effect it like this, and at that I'm not usin AC that much tryin to stop the gas usage. Has this happened to any of you and what did you do???

 

I usually get 20-23 ish with all city driving. Highway I get 27-32 mpg or so. My air is almost always on. The weird thing is that every once in a while mileage jumps up or down, but only for a tank. I've got to say that it probably isn't right, my guess is to check alignment and all the other basics (tire pressure etc.) and then check it out. Out of curiosity, where in FL are you at?

 

Odd. I drive highway mostly, and get about 33 to a gallon. That's with the air on. Try getting gas from a different station for a few tanks and see if the problem is solved. If you have a dirty filter, then you should really change it.

How many miles do you have, and when did you last get new plugs?

 

^ has good point. Some gas stations will give me 16 miles to the gallon while other give me another 5.

 

What kind of gas are you putting in the tank?
I stick with Chevron regular and I get around 25-27 mpg. Some other things that might play into your mpg are spark plugs (minimal) or a loose o2 sensor (major).

 

i usuallly get safeway gas or shell gas. i get about the same as ghostrider, 25-27, but about 30 on the freeway.

 

i dont mean to hijack ur thread, but since where on the subject, is puttin supreme unleaded a bad thing, or is it better for your car. id rather put regular, but i dont know if it will under perform

 

dont know how you are getting that ****ty of gas mileage cause i have the same kind of car and i am getting 25-26 mph and i drive hard and rev the engine high

 

putting higher octane into a car is always a good thing. it will burn cleaner and better than regular but for the lancer i have no idea

 

Higher octane gas: harder to burn (to avoid detonation under high compression/boost (take Evos or Celica GT-S's: one is boosted, the other has insane compression) or timing but burns more effectively. Lower octane: more readily combustible. That's a very basic explanation but conveys the point. Seeing as the Lancer does not normally run boosted nor under high compression or from some crazy timing advances, running 87 is perfectly fine. That is what I run and my mileage is around 350~ per tank, and at that point I have about 2-3 gallons left in the tank (since my average fill up is about 10-11 gallons, in a 13.4 gallon tank, depending on how adventurous I feel with the fuel light on. Take Road Race's ECU, they advance timing and play with the fuel curves, necessitating the higher octane requirements to make more power.

 

I get like 2o miles or so to the gallon also. Mainly hard city driving and also high speed highway driving alot. You also gotta figure alot of us have alot of weight in the trunk. Plus I'm sure a heavy foot has alot to do with low gas mileage.

 

Id go with all ideas above, start by chaning gas stations, then o2 sensor and spark plugs, then try out alignment/pressure... other than that, go back to the dealership and tell them to run a diagonistic on it, maybe your ECU is just fubar and you dont know!

 

i tried between Shell and Exxon 93 octanes.. Shell 93 octane works the best in my car. im gettin 30-35 on the higway

 

For some reason, when I used to use Arco gas (years ago), I got the worst mpg, and I swear their pumps were wrong (putting 14.3 gallons in my 14 gallon tank when I thought I had 1/8 tank left)

And as for octane, read what Pjal84 said. Higher octane is just harder to ignite and burns slower. A naturally aspirated Lancer will see little if any gains from higher octane, unless you adjust the timing and fuel mapping. Boosted engines have a need for it, though. But if you really want to waste your money, anything up to 93 octane will not do anything bad to your car either.

 

Well, I'm beginning to think it was the gas that i used this week it seemed weak when i was pumping so its prolly just that.
Thanks!! and i'm in Miami. =D