MPG Problem

I think the problem is Costco.
I'm getting a Prius (trading in my 08 Tundra)
I always get 3-4mpg less when I use Costco

 

RBK,
A few points.
- does the new tire has the same diameter as the GY Integrity? If not, the MPG needs calibration to compare with old values.
- which is the new tire? Most "normal" tires will degrade your MPG since the OE ones are LLR (low rolling resistance). Pick one with LLR next time. However this alone won't explain the severe drop you see.
- what is the tire pressure? A drop from 40 down to 32/34 (Toyota recommended) will cost you 5% MPG.

jasper7821, are you talking about gasoline?

 

Were you really getting 51-54 mpg at 70-75 mph? At 65 I can get that even in Winter, but it seems a bit on the high side to me at 70-75. However, the terrain here is pretty hilly and that doesn't help.

 

What tires did you buy? What size did you have before (were you still on the stock Integrities - 185/65R15) and what size did you purchase?

On what tire pressure did you run before? What is the current tire pressure?

Did you use Costco gas before? Is there any other change you've made, such as using different wheels, having break work done, different driving pattern?

Not everything is solveable, but chances are someone will help you find the cause. Even though the drop for you is pretty dramatic, I would attribute it to the new tires. The Integrities may not be popular with everyone on PC, but there is no doubt they usually offer high MPGs in exchange for other performance "issues."

 

i agree w/ most of the above...
- new tires reduce economy for the first 3-5K miles
- cold weather recently throughout the US (including here in SoCal) reduced economy
- finally, COSTCO doesn't inflate to max pressure (44/40), but rather stays in the 36/32 (or lower) range. You'll need to do that on your own which will help your cause

 

Low LOLing resistance?

 

LLR = "Limited Life Retread"

Tom

 

I just had 46Mpg on a Tank of Costco Octane 87 in the bay area. On my new tank of Low Cost 87 Octane from a local discount non brand, I am now getting 55MPG

Is it possible that Costco sells lower quality gas that is causing such a huge difference?

 

Your 51-54 MPG with 70-75 is well above mine so far!
The inflation with nitrogen (probably done at the door sticker recommendation) and new tires are prime suspects. Most gas comes from terminals that are shared by several suppliers. If the gas is rated 87 its gonna give 87 worth performance...additives etc for cleaning may come into play long term but that won't affect MPG now...ethenol mixtures will, regardless of their source.