[Diesel_Dave]

Well, I have to admit that some of you ecomodder veterans were correct. I heard about some of you talking about making sure you always use the same fuel pump every time you fill up. I thought that probably wasn't necessary, because I didn't think there could be that much difference between different pumps. After my fill up this morning, I realize that's probably not true.

Here's what happened:

My tank is nominally 34 gallons. I always top off very slowly until I can see the fuel level in the neck (to try to get consistent readings). Therefore, my typical fill-up is between 34 & 35 gallons. The most I've even put in one fill up was 34.9 gallons. Today, I used a different pump--and it read 37.5 gal! There's no way that can be right!

Last tank was a record for me (33.9 mpg on 34.8 gal), so at first I thought that maybe I didn't get the tank completely full last time. Therefore, last tank would have looked artificially good, this one artificially bad. However, I highly doubt that's the case--there's just no way I can fit 37.5 gal in my tank. Plus, my calculated mpg on this tank was 28.5. That's the same as a tank I had 3 tanks ago. However, the average of my daily log FE was 10% higher this time than it was on that tank.

I'm going to dig up my receipt from last fill up and find out what pump I used then. From now on out I'm going to try to use that pump every time.

This thing kinda pisses me off, but maybe I should look on the bright side: this was my 3rd straight kilotank and my 3-tank avg is 113% over "EPA".