That's why you have to look at an average of all the fillups over time rather than each one individually because of so many variables
1991 Toyota Pickup 22R-E 2.4 I4/5 speed
1990 Toyota Cressida 7M-GE 3.0 I6/5-speed manual
mechanic, carpenter, stagehand, rigger, and know-it-all smartass
"You don't get to judge me for how I fix what you break"
I thought I was doing so much better as my ScanGauge read 37mpg for this last tank and also showed that I used 12 gallons. I went to the station and pumped really slowly as I had read about here. To my surprise, it took 13.28 gallons to refill my take and knocked my mileage below 34mpg. Something is wrong; time will tell. I've used 1/4 tank since then only getting 33mpg.
I always pump the same way (full blast) and stop when the pump clicks the first time. and I always use the same pump. Its not always the same side, but the same pump. It doesn't really matter exactly how you do it, just stay consistent. Iv been getting really consistent #s as well. I mean I am trying to get better, but it seems I've hit some sorta brick wall. Things I would check tho, are tire pressures, if a brake is dragging, spark plugs, and of course O2 sensor...
There are a number of gas stations that have some weird presets to cheat customers out of gas. Some will do even amounts ($10, $20, $30, etc.), some will do even gallons (5, 10, 15, etc.), but when they reach those numbers, your gas should be correct. This is because weights & measures typically do either increments of 5 gallons, or increments of $10. I saw a story on it a few years ago. Dateline or 60 Minutes or one of those had a special tank that was calibrated, they got odd amounts, and caught DOZENS of gas stations that had pumps that would not always read right.
So your 5 gallon hypothesis may have been based on the correct measurements. Might try a 2 gallon can.
Looking to trade for an early 1988 Honda CRX HF (Pillar mounted seat belts)
I do go to the same station every time.Not the same pump cause it's a very popular station and usually cars waiting in line. I'm going to keep pumping slowly and top the tank off. It just threw that one tank off some,but my life time and 90 day averages weren't hit that hard.
As busy as this station is I'd think they'd be reported quickly if they tried to cheat on the pump calibration.
The plugs have been changed about 6 months ago, tires have 40+ psi. The front brakes and rotors have been replaced a month or two ago,but I've not been into the back brakes. I'm going to replace the drums and shoes sometime soon,but they aren't making any noise.
I'm not messing with the O2 sensor unless I see a check engine light and the scangauge reads the o2 sensor code.I'll leave that to the civic people.