OT- Interesting gas mileage info

[ShanaMama]

We've been tracking our gas mileage over the past couple of months, to try & figure out which gas stations get the best mileage. Interestingly, I found that Exxon/ Mobil (no difference) won by far, at around 26 mpg. The cheapest around here is Wawa, which consistently got the least mpg, around 21-22. All the other off-brands, like Sunoco. Lukoil, etc averaged around 23 mpg. I never expected such a range, but I'm glad I've been keeping track.
Hope this info helps someone.
PS- Don't know if it matters, but I drive an 01 Impala with high mileage (160K).

[KBecks]

Interesting. Are your driving patterns the same over each tank of gas?

[SnuggleBuggles]

That's what I was wondering too. Same ratio of highway and stop/go driving? Tire pressure the same? Carrying any extra weight in the car? A/C use?

Beth

[ShanaMama]

Yup. I commute to work every day, about 35 miles round trip, 1/2 highway & 1/2 city.
Weekends we either do nothing or go visit grandparents in NY, so that's also pretty consistent.

ETA: Beth, it seems like we were both typing at the same time. To answer your questions, I can't guarantee scientific accuracy, but I've done the calculation with each tank of gas over the past 4-5 months. So there has to be some variable (heat/ ac, more luggage on the weekend, etc.) but overall this was a strong pattern. I was very surprised, that's why I decided to post.
Maybe I should've bought stock in Exxon before I posted this, lol.