Gas mileage

dodge
gasoline
dakota
fuel-economy

#1

My primary vehicle is a 2005 Dakota. I use 3 primary gas stations in

Parker, Colorado. I keep close records on gas mileage. I decided thru this summer to mix the stations I use to 3 each over 3 months. I found significant differences in gas mileage, up to 10% to 15%. At station #1 mileage is 18.2 MPG, station #2 16.8 MPG, and Station #3 16.0 MPG. Station #1 is always greater than the others. I suspect the difference is either the lower heat content in enthanol fuel or poor measurement. What do you think?


#2

MTBE was banned in CO in 2002. Any other chemical that raises the octane rating should be allowed. TAME, ETBE or ethanol are usually the only ones used. Check the 3 stations to see if they all use ethanol and how much is used. Differing levels of ethanol or the use of ETBE could account for the difference in mileage.


#3

Seems a reasonable explanation. How many measurements (tank fills) did you do at each station? That info is needed to establish a standard deviation and thus a significance level.