21 mpg now 16 mpg Costco Gas?

[Tgrds]

I have been getting on average 21 mpg using 87 octane Costco gasoline since I bought this rig back in April now the last three tank fills I am getting only 16 mpg and my driving habits are exactly the same.

It is cold outside as it is now becoming winter up here in the northwest, so I figure they either changed the gasoline formulation for winter or something weird is going on with my 4runner. Either way it is irritating. You guys have any thoughts on this?

 

[Jesse1983]

My mileage has taken a hit in the last few weeks too. I changed my air filter today, hoping that may help a bit.

 

[Ben_Mueller]

Me thinks "winter" gas has gotten here... More ethanol = Less MPG...

 

[nah2323]

Me thinks "winter" gas has gotten here... More ethanol = Less MPG...

+1. Winter gas is in effect. When the price drops a good bit quickly for no reason, it's the typical winter mix change over.

 

[Tgrds]

+1. Winter gas is in effect. When the price drops a good bit quickly for no reason, it's the typical winter mix change over.

That's what I figured, this is "really irritating" since I am paying the same price per gallon as I did before winter hit, and now with less miles per gallon.

I am going to stop using Coscto gas for a while and take a look at one of the Chevron gas stations around here to see if it is any better. Probably not but worth a look I figure.

 

[dgarci24]

you should either switch to Chevron or Shell they usually use less ethanol and I usually get 26 mpg on my 3rd gen. which is pretty weird because the rating is like 19/22

 

[westwind77]

Most states are E-10 (10%), and it varies very little from summer to winter. Technically if they were selling over 10% they could get into trouble. It is easy to test for the percentage, good test kits are out there and not too much money. I have one and have done random tests, little if any variation, at least here in MA. Different states might have different rules or additives.

 

[cucumber pie]

The cold weather also affect your mileage

 

[JS5thGen]

Mine dropped about an average 5mpg as well....this week....Costco!

 

[luv2eat]

So, I'm not the only one who thinks Costco gas sucks:hello:. When I owned a Infiniti G35, I used to religeously fill it up with Costco gas. After a couple of years, the engine started knocking. It would take 3-5 consecutive fill ups with better quality gas for it to reduce the knocking; the knocking never went away, which was my biggest reason for getting rid of it. With my other cars, I did notice the MPG go down. No more Costco gas for us.

 

[RonMAIDEN]

Is that 21mpg overall driving since that's a solid hwy number but 16mpg is decent if it's all city driving but pretty bad if nothing about your driving changed.

 

[OCMike]

2 gas stations I won't touch: Costco and Arco.

 

[oldsweng]

I only buy major brand gas, except ARCO. Bottom-of-storage-tank gas like the cut-rate places get from wholesalers is not such a great deal. I learned my lesson when I had my M3. It loved chevron and 76 premium and choked on cheapo premium.

In actuality mileage doesn't matter - cents per mile is the calculation to make. When premium is within 20 cents of regular I buy premium because the mpg increases and the cost per mile is less.