Could I have gotten a lemon?

[Spittin Game]

All of a sudden it doesnt feel like there is as much power as when I was test driving other 300c's. And I am averaging 12.5 mpg, and thats with about half highway and half city. My car only has like 550 miles on it, but still. Its worrying me, b/c at first this car had balls out power, now its "ehh" and the mpg is absolutely horrible. I have to fill up every 220-230 miles, and its over $50 each time.

[OoTLink]

Could be your gas station using E10, but it could also be a bunch of other things - dirty air filter, perhaps bad spark plugs, or time for an oil change? Bad oil? (Maybe they changed it with 10-30 instead of 5w20?)

I get 12-ish mpg in vallejo with 90% city driving myself :\ Out here it seems to be averaging a little better, I dunno, over a 560 mile trip 100% freeway/highway I only got 21mpg, but I'm not complaining because I had to pass enough trucks and deal with crazy situations that well, it was probably justified.

Dunno *shrug*

[TypeR0149]

yea I would do more research

[Spittin Game]

Even if I did get 21 mpg on the highway it would be a lot better. I mean, it feels like it doesnt have any "oomph" anymore down low, could I just be used to the power now??? Could it be possible that its the break in period? I just passed the 500 mile mark today, but filling the tank up every 220-230 miles is annoying. I have been using regular, should I try using premium? In my Escalade I always used regular, it got not only better mileage than the premium but ran just as good if not better. BTW this is gas form Costco.

[Moose]

Originally Posted by Spittin Game

Even if I did get 21 mpg on the highway it would be a lot better. I mean, it feels like it doesnt have any "oomph" anymore down low, could I just be used to the power now??? Could it be possible that its the break in period? I just passed the 500 mile mark today, but filling the tank up every 220-230 miles is annoying. I have been using regular, should I try using premium? In my Escalade I always used regular, it got not only better mileage than the premium but ran just as good if not better. BTW this is gas form Costco.

I feel for you...

You might want to take it in to your dealer and see what they say. Since it's not throwing any codes I doubt they will find anything wrong. But at least you can make a recording in the system that you are concerned and if it does turn out to be a lemon you have the documentation.

[OoTLink]

Do that, but I wonder if resetting your car's ECU and such would help any (unplug the battery and let it sit a few minutes?) Don't forget to calibrate the ESP and MDS afterwards *nod*

[MrHappy]

You should be using 89 actually. (87 being regular here so not sure what it is there). You can use premium but unless you have a programmer to warrant it, I personally would stick to the 89.

[kevenj]

The FIRST thing I would do is buy gas someplace else just to see if that is the problem.

If that is not it then use the search function here to find links to "Throttle recalibration" and "MDS reset procedure". If neither of those procedures work then take 'er in cuz something isn't right. If I drive my "C" like I stole it I still get 15mpg in town; and it certainly has plenty of power. Of course mileage depends a lot on what your 'in town' driving consists of; If you are in a very congested area where you are sitting stopped in traffic half the time, remember you are getting ZERO mpg when you are idling. That still does not explain lack of power though. If the dealer says he can't find anything wrong, insist the service writer take a ride with you in a new one off the lot so he can't BS you.

[OoTLink]

Maybe your carpet is in the way of the gas pedal too? O_O Stupid thought, but worth a check

[Spittin Game]

Thanks guys!

I will try a different gas station next time, even though I never had a problem with my other vehicles theire. Maybe this one is tempermental.

I have no clue what ESP and MDS calibration is...

And as for the carpet under the pedal, thats a good thought. That actaully happened in my other car, I had the winter mats in and it got under the pedal, as soon as I moved it, it was like a new car all over again. Maybe that will fix the power issue, and maybe the gas station change will help with the mpg.

We will see, Ill keep you guys updated! Thanks again!