This morning I was first in line at Costco. I got there right as it opened up at 6:00 a.m. It turned out to be a good thing, because 10.635 gallons later I saw that my 412.6 miles worked out to be 38.80 miles per gallon.
I went nine days between tanks.
This is the third highest mileage figure this year, bringing my average mileage for 2007 up to 36.70 miles per gallon.
It is also the sixth consecutive tank of over 400 miles. I noticed this time that I actually went 406 miles before the reminder light even came on.
I suspect this spike in fuel economy may be due to the tire that was leaking that I had replaced. Proper tire pressure really counts!
If my next tank is also close to 38 MPG, it should remove any doubt that this tank had high mileage due to putting in less gas than normal. But I did run the pump until the third shutoff click because I wasn't expecting it to turn off in the 10 gallon range.
A nice tank overall.