also, i go about 75-85 mph on the highway so put that towards the mpg.

 

Badassgrl,

i have the same car as you do and you do have the TPMS. It only turns on a red light on you'r dash area where the speedometer is. It will trigger the light when any one of you'r tires show's pressure of less than 28psi I believe. You will have to check this figure. It doesn't tell you which tire, just informs you to check-em all.

 

I just filled the tank on Sunday and have driven about 75 miles to date and the tank is half empty. 75???? This never happened before. Anyone have any ideas before I call the dealership?

 

Just a quick question cause it does not seem like anyone has asked. "what kind of new tires did the dealer put on" I am just curious. Maybe less rolling reistance. I drive moderate. I get about 600 kilometers before I get nervous enough to fill it. (Not like I let it get that low too often. Not good for the fuel pump, anyways) I just had some new Michelin Primacy Mx4 Grand Touring (blah blah) tires put on. I have noticed that I am running just over 8 kms per hundred. (Sorry my u.s friends. No idea miles per gallon) Used to run 7's with my Toyo's. Just waiting for the warm weather to hit. See where that puts me. Could be the new tires.

 

A couple of things to note here.
First, take a look at your tail pipe.
Is it covered in black soot?
Does the area near the tailpipe have any black soot on it?
This could be a sign the engine is running a bit rich.
Also, you meentioned you got new tires.
Are they the same size at the old ones?
That could make a big difference in mileage,espicially if the new tires are a bit smaller than what was on the car.
It is doubtful that a standard oil change would have any effect on the mileage.
My suspect would be the tires.
Sometimes vehicles take two different tire sizes from front to rear.
I am assuming our Mazdas have the same size all around but, that in no way can speak for a dealer mechanic who should know what tires are suppossed to be on the Mazda.
I would check just to make sure they are the correct size.
Again, that little mistake would cause the mileage to drop.
Bob.