mileage took a dive
 

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.

um... oh no? just gonna complain or got some ideas about why?

If you pumped slower than usual, you pumped fuller than usual. Slower pumping is like topping off.

This is what I hope happened. I've never gotten over 13 gallons into the tank on a refill before.I looked up the tank size and it's 14.1 gallons; all those times I worried about running out for nothing. The only different thing I did this tank was more pulse and glide,which I thought helped. I just got 38mpg coming back from the grocery store( per ScanGauge). We have had some wind and rain lately and I did have to go into some shopping mall parking. That could account for the bad mileage on this tank so far.

Looks like it was the slow pumping top off that threw the mileage off. I topped it off again at about the same miles and got 35.8mpg; about what I had been getting recently. The ScanGauge was off again, but in the opposite direction; showing 32.9mpg. I'll have to keep on topping off to keep my gas log correct.

Sometimes I think the Chevron station I fill up at changed their calibration and charge me more for less gas!

I usually run my tank pretty low,so if it ever goes over 14.1gallons. I'm calling the Dept of Agriculture division of weights and measures.

I filled a 5 gallon gas can for the mower at the local country station a few years ago and they tried to charge me for 8 gallons. The pumps were WAY off.

Since i started a log on this web site and read others logs it seems the mpg will go up and down some what until we post many tanks to get a good average.

I had this suspicion once of a Cumberland gas station (I believe it's Gulf gas) I was so sure of it in fact, that I got a gas can and filled it up to the 5 gallon mark and logged how many gallons it took (about 5 gallons) and then emptied the gas into my car and did the same thing at the station across the street, filling the gas can up to 5 gallons again which was also a very similar number. So, to my disappointment, I had to drop that hypothesis.

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

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...:thumbup:

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.

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.