i would hate to know how bad mine is...

this is on the vette

 

We have an '02 Trailblazer that can give you an instant real time reading as well as an average per tank. I keep accurate records with every fill up and have found the average per tank is always about 1.5 mpg too high on the gauge than it is with a calculator when I've been driving all city miles, but when on the highway I find it to give an accurate reading on the average miles per tank. Taking that into consideration, I'm guessing it stands to reason that the instant real time reading is probably a bit too high in the city as well, but I still enjoy using it because regardless of if it is a little bit too generous, it will still help me see how different driving techniques can help save gas. For instance I've learned that on this truck it will shift into overdrive when going as slow as 30, which puts the rpms at around 950. I don't like running it like that, but I learned that by shifting to 3rd I bump the revs up and the mileage reads the same because the engine is running more efficiently. What I'm saying is that even if the reading is off, as long as it's consistently off, I can still benefit from it. But I hear that the ScanGauge, when calibrated properly, is very accurate.

 

I'm glad my 98 limited came with it, since it's my DD.

 

I once got the one in my wife's old 97 Chevy Blazer to read 99 mpg.... of course that was down hill with my foot off the gas.. was interesting to watch the instant mpg..

 

lol, as a joke you should take a picture going down hill when it reads 99 MPG and go on a forum for Prius drivers and be like "HA!!! SUCK IT!!!"

*i hate the Prius. smug-emitting pieces of ****.

 

nevermind someone beat me too it.

 

Auto Meter makes an Ecometer for 70 bucks that does quite a bit. Its on Summit Racings website. http://www.summitracing.com/parts/ATM-9100/