different gas, different gas mileage

On 3/14/10 5:38 PM, in article ,
"Ashton Crusher" > wrote:

> On Tue, 02 Mar 2010 22:33:51 -0700, Ashton Crusher >
> wrote:
>
>> I've always liked chevron gas because it has techroline, which is one
>> of the best fuel detergents. But I've noticed lately that when I buy
>> Chevron my 2009 PT seems to get about 2 - 3 mpg worse gas mileage. My
>> other typical fill up is some "FastGas" type place. This change has
>> happened often enough that I'm pretty sure it's not completely my
>> imagination. Anyone else noticed such a change from one brand to
>> another? On the FastGas I usually get 24.5 on my typical driving
>> cycle, 70% commute, on the Chevron it drops down to about 22.
>
>
> Again I have seen what 'looks' like an immediate drop as soon as I put
> chevron in. I had the "fastgas" stuff in and just before filling up I
> reset the mpg computer and drove the last mile. It ran up to over 24
> mpg during that mile. Filled up with Chevron and since then I have
> tried over and over doing resets and driving a mile and the best I've
> been able to do is almost 22 but mostly it's barely breaking 20. I'm
> going to do the same thing on the next fill up except it will be the
> reverse, I'll do a "last mile" check on teh chevron and a first mile
> check on the fastgas.

Interesting that its Chevron.

My previous car ('08 Nissan Altima 4 cyl) regularly got two MPG less on any
brand but QuickTrip. My new car ('09 Infiniti G37s), over the first 7700
miles, has gotten consistently 3 MPG less on any brand EXCEPT Chevron.

I use the mileage computer as a real-time reference, but do the actual
calculations the old fashioned way (miles driven divided by gallons used).

It appears to me the variable is the cars themselves rather than the gas.