I recently purchased a used 2009 Civic Hybrid with 22k miles on it. Since then, I've averaged about 32 mpg (according to the display gauge). My hand calculated shows that to be accurate within about 1-2 mpg.

I use odometer setting B to gauge every tank of gas. When I fill up, I tend to read around 40 mpg around the first few miles. Then it drops to about 32 mpg with a couple bars left on the gas tank. I then refill the gas and start over. My overall mpg reads about 34 read not (on odometer setting A which has logged about 1200 miles since I purchased it). I'm trying to figure out why I cannot stay at least near 40 mpg consistently.

I've noticed a couple issues that are worth mentioning.

I only get to about 40 mph when I started resetting my tires to 40 psi (done at gas fill up). I think there is a slow leak in one tire which seems to drop to 30 psi before the next tank of gas. Would decreasing psi in one tire (or unevenness in psi) cause this low of a mpg? I took it to Honda and they told me that all of my gas sensors on the tires have a slow leak and should be replaced. I'm thinking about doing it but they are going to charge $450. Has anyone had a problem with the sensors leaking?

It has been 90-105 here the last few weeks so I have been running the AC constantly on high. It doesn't cool well in city traffic which I see may have been a known problem for the cars. Could the AC be responsible for a 10 mpg drop?

Thanks for any comments. I'm new to hybrids and have read tutorials about hypermiling but I think I have more basic problems than need to be solved.