I live in Portland Oregon and have had my Prius since Feb 2005. Mileage has been averaging 45mpg since day one... except for the last two weeks. Mileage has been hovering between 35 to 39mpg. The Prius has 13K on it and is in great shape except for the mileage in the last two weeks.

I'm thinking I should take it to the dealer so they can check it out. Am I over reacting ? Can the dealer really do anything about this? Any opinions out there?

Thanks

 

What has the weather done in those 2 weeks???

 

With 13K, you are well within the ordinary range for warrante service. But it also beg checking:

1) tire inflation 42/40?
-- tire rotation due?
2) oil level 1/4 inch below "F"?
-- oil change due?
3) driving routine change?
-- slow speed warm-up?
-- multiple short trips with cool-off periods?

Good luck!
Bob Wilson

 

Thanks for the replies. The weather has been in the mid to high 40's with rain almost everyday. Tires are at 38psi and are rotated every 5K, oil is changed every 5K too. The multiple short trip thing could apply, but I'm thinking not.

 

Rain can drop my mileage by 10 - 20%, especially if I have to use the defroster. My guess is that the rain is causing your mileage drop.

Dan

 

Agree with the rain, big mileage hit. Tires could be a little harder.

Bob Wilson

 

And you want to make sure you have a 2psi differential between the fronts and the rear. Fronts higher psi than rears. I'd move up to 40 front, 38 rear and see if that helps a little.

You also could have a batch of poor gas. Winter formulation of gas generally will lower FE quite substantially.

 

Ok Jerome Im sorry to dispute your comments, However, i dont claim to be an expert on driving tips on the street, but ive been racing cars (formula type) for 26 years and we are not driving race cars on the street here. Tires should all be the same, and if anything the REAR tires should start out with 2 LBS more PSI due to the fact that front tires will "Grow" more than rears due to the fact that they are the ones that take more of the brunt when braking , as well as turning the wheel causes more friction in the fronts therefore bulilding more heat, which as we all know causes expansion which causes air pressures to climb. And yes the winter additives for gas will cause much worse milage. I run my prius stock tires at 50 psi here in Chicago. Temp average is about 30 I lower them to about 35-40 if there is snow so they "Bite" a little better. Sorry about the rant just my 2 c. Dean

 

I'd forgotten to ask if he'd maybe gotten a tank of ethanol laced gas. Regular engines run cooler with it but the decreased MPG effects are more visible in a hybrid.

I know there have been some debates in different areas about ethanol vs. other fuel addatives. Have any states made changes this year in MTBE?

Bob Wilson

 

Aren't those cars that you race rear-wheel drive?