Why would premium gasoline get you less MPG?

[ChrisBlair]

Who's website is that? Just because it's online or in print, that doesn't make it fact. I've had to call up the manufacturers of chemicals and tell them that their data is wrong on Material Safety Data Sheets. When you have a senior VP on the phone walking him through his company's error on safety information for chemicals that can kill people, you realize that you can't believe everything you read. If it looks screwy, it probably is screwy.

[ChrisBlair]

Originally Posted by Mick1

I can make my DIC display 0.00 MPG and 99.9 MPG. What do I win?

[kevinw]

my 2LT is averaging all around aboiut 17 MPG at this point, hope it gets better and thats driving conservately, and it has aboiut 476 miles on the car now

[Mr Monte]

If your engine is tuned for regular & you run premium your performance & mpg will suffer. Higher octane fuel burns slower than regular. It amazing me when I hear people say they "treat" their car to premium sometimes.

I have found my cost/miles is less using premium on a premium tuned engine than using regular on a regular tuned engine.

If you play too much with the extra power using premium on a premium tuned engine then your mpg will suffer.

Our 2000 SS 6 speed manual gets 30mpg hwy but our 2012 SS/RS auto gets 26-27mpg hwy. City/backroads mpg is all over the map depending on traffic & fun factor but typically runs 16-18mpg on both.

[Mick1]

Originally Posted by ChrisBlair

I can make my DIC display 0.00 MPG and 99.9 MPG. What do I win?

haha. As you can see, I only drive 800 miles or so a year on this car so how much gas it consumes doesn't bother me. My problem is when to take it in for service because the dealer keeps on saying my service is overdue and I don't want to service a low mileage car

[PalmerGA]

Originally Posted by sean90

Anyone care to share their estimated mpg on a trip that is 21 miles, 19 freeway, with light traffic? Assume your not punching it because you want to save that extra gas money for spirited weekend driving :p

21 miles is not enough to give an estimate. You can get pretty good numbers if you reset the DIC estimated mpgs every time you make the trip, but it's not an accurate reading of what your will get "per tankfull", which is the way to estimate mpgs. If you've ever noticed, cars usually get their best mpgs when the tank is full and it gets less as the tank gets used up. So, if you fill your tank every day, go easy on the pedal, and reset your DIC mpg estimate every time you make your 21 mile trip... you sould probably get mid 20s - but that's not a very reasonable scenario.