Here's one for you...I just ran through my first tank of premium today and calculated my mileage to be 19.4 MPG...my previous two tanks of regular had gotten me 19.8 and 20.1 I believe. Same routes everyday, no highway driving...basically I didn't change my driving habits at all for the tank of premium, and it didn't help a bit. What do you make of this?

Maybe it'll take a few tanks of premium to notice a change, if I notice one at all?

 

maybe go with the 89 or whatever less grade of fuel and get more of a chance of detonating....and save like 10 cents.....but its ok.....its no biggie

 

You say that as if you think premium is supposed to net you better gas mileage??

Our engine has high compression and was designed to be used with higher octane fuel. Read the stickied thread at the top of this forum.

 

Running the air conditioner more than normal would make that big a difference. I think its the conditions affecting your gas mileage more than the gas.

 

What i've been noticing is that you get different mileage from different stations (shell, mobile 1, 76, cheveron etc.). On my other car, I was getting 16 mpg average on crappy arco 87 and it jumped to 18 mpg on 87 of 76.
89, and 91 seems to make little difference, though. I seem to get better on mobile one than 76 as well.. just a theory, though.

 

The difference between 19.4, 19.8 and 20.1 isn't enough to say there is a difference due to fuel. I drive the same way each day to work, always use premium and my fuel economy can be anywhere from 19.6 to 22.0 MPG. Since we're all human and driving conditions can vary, even minutely, I'm sure you are creating some small driving changes that caused the difference in fuel economy. Now if you had a 3+MPG difference, then maybe I'd say there was an issue, but you'd have to repeat it more than once to validate it. Just one time on one tank of premium doesn't tell me much statistically.

With that said, the car was made to run on premium, and the owner's manual says you should only put in regular is premium isn't available. To me $3 a tank isn't enough to warrant screwing up my car.

 

Shame on you for putting Arco. I think if you plug in knock sensors you will see 89 pings more. Someone want to do the test?

 

At least you don't have to put in 93, OR 89 lol. Thats all the choice I get. $50 today and it took 15.2 gallons. That is upsetting lol. At least its good for 500 miles and not 375 like an SUV.

 

I don't know how you guys are getting such high mileage per tank. I only average 300 and around 350 mile per tank at best. I have test pipes but I wouldn't think that would do it. I wish I paid attention to the mileage b4 test pipes.

 

We have a sticky about running gasoline less than 91 octane. Geeeeze!

 

WOT,AC on 3 clicks. 181MPH on I5 North. i wonder what i was getting...???

 

Yep, lower octane will net lower mileage. The reason is that our ecu is designed to run on 91 +, and if you run lower octane, it will compensate by changing the map, which will cause your mileage to go down a little.

There are factors, like knock retard, which will occur from running low octane gas. The ecu will retard the timing and add fuel to compensate, which will reduce mileage and power.

Running the premium will give you the best results when it comes to gas mileage and power, as the ecu will advance the timing and adjust the fuel based on the lack of pre-detonation it detects.

 

How could you guys average 16-19 MPG? I average 13 MPG, I drive easy and the car is fairly new (2900 miles).

 

I average about 20.5 in the city.

 

^Ditto. I've gotten as high as 28mpg on the highway, cruising at about 70mph.

 

Can somebody stop ignoreing every body that asks the question "how do you get 19 and 20mpg" I wanna know also because I don't get anywhere near that! Sometimes I get 15 or 16mpg but not 19 or 20mpg I shift like 2500 or 3000rpm and get too 5th or 6th asap when I'm trying too save gas and still no luck!! WHAT'S THE SECRET?!?!

 

Now how can you really tell if you gas consumption has changed with 91 oct vs 89?
Unless your doing it in a lab type enviroment, there are way to many variables which could influence your actual MPG

 

wow that is horrible gas mileage, you must be doing something or something is broken to get 13

 

If I just drive to work (4.5 miles) and back everyday I get 14.x mpg. It's because I avg less that 15 mph and idle most of the way there. As soon as I mix in some highway miles it goes up. If I do 50/50 I get about 21 mpg. Strictly highway I get between 26 - 27

 

Have you had a tune-up recently? Maybe your car needs one. I make sure I follow all the service schedules. I also make sure the tires have proper pressure because that can take like 1-2 MPG off too. Just for comparison because this recently happened: my wife drives a Volvo XC70, we drive to MD quite frequently. Our last trip I didn't verify tire pressure and got 24.2 MPG. This trip I made sure I checked the tire pressure, put in some extra air, and got 26.0 MPG. The road conditions were similar, and we always set the cruise for 72 MPH.

One thing I also notice is a lot of people racing up to red lights like they are getting to pole position. Rarely to these people ever get more than one or two cars ahead but racey race, bob and weave across lanes trying to get even further ahead. I just laugh when I end up sitting next to them at the next red light. I'm sure that costs another 2-3 MPG. I don't drive like a granny, but why am I going to rush to get to a red light. If I coast a little I may not even have to stop and usually get a jump on the stopped people because I'm still moving.

In summary: regular tune-ups, check tire pressure, no racing to red lights where you're going to end up idling and wasting gas.