Got an Ecometer by AutoMeter last week

[BEEF]

one thing that could be affecting the meter reading is how you are filling your tank. if you don't fill up the same way or use the same pump every time, you can get variance.

I always fill it up to the first click. even this has some variance in it as sometimes the gas foams more than others.

I would say you could average out 3 tanks and what the ecometer does over those 3 tanks and do a comparison with that.

I will say that the difference is about a half gallon so I wouldn't think that the variance I am talking about would have been that much but it is still a factor to consider.

I personally have a scangauge and an ultragauge. I keep one in each car.