TALLAHASSEE, FLORIDA -- On Friday 7-11-08, I filled my Dodge Durango at the Tallahassee Costco gas station. I have owned my truck for several years and mainly buy Costco gas. My truck has according to Dodge a 25 gallon tank. The distance to empty (DTE) digital gauge showed 12 miles, and my average MPG is around 14.5. When the truck is this low on gas, I usually put in 22-23 gallons. The most I have ever put into it when the E was on the DTE gauge was 24.5.
The pump at Costco indicated I put 26.5 gallons into my tank. After filling, I showed my receipt and my owners manual to the employee, who referred me to the store manager. After locating him, I was eventually told they would look into it, and I gave him my member info and phone number.
I received a message from another subject at the store the following day stating they had performed a test on the pump and I could call back to get the results. I'm not sure why he did not just tell me, but at any rate, I returned the call and was never able to speak to this employee on the first couple of tries, and then learned he was on vacation. I asked for whoever was in charge, and was transferred to another employee.
This employee told me they had weights and measures check the pump and they were actually putting out a little more than one gallon per indicated gallon.
Perhaps this was a one time thing, but I wanted to post this information in the event anyone else notices a pumping discrepancy.
Since there is no way I put 26.5 gallons into my 25 gallon tank, I figure what happened was that I actually pumped in at most 24 gallons and paid for 26.5, which is about a 10% rate of error in Costco's favor. This bumped the price from 3.93 per gallon to about 4.32 per gallon.
This seems like a stealth way to increase the profit per gallon substantially, since most people don't know how much gas their vehicle can hold or usually takes based on gauge position.