First,

I realize the frustration at feeling attacked when posting a valid question. However "Lemon"? Thats overstating the case a little isn't it? A lemon is usually used for a vehicle that is undrivable. Even if you get 24mpg you are better off because you have an SULEV-II vehicle getting 7MPG better than the V-6 does (freeway ONLY for the V-6). Thats not a lemon. It isn't getting EPA but many vehicles don't reach their EPA estimates in real world situations. Couldn't we have selected a title for this thread thats a bit more descriptive and not hyperbole? Its just likely to create even more attacks....

That aside. You are looking for a discussion of things that can cause low MPG and not an attack on driving skill. There are plenty of examples that its not always a defect or even driving skill that causes low MPG.

Low MPG can come just from the driving conditions one subjects the FEH to. I (for example) drive a 9mile trip to work and back. These short trips don't allow the engine to heat up much so the EV mode never occurs. In fact under such driving conditions even a conventional engine will fall short of the EPA estimates. If I drive on a longer trip I can get 3-5MPG better mileage than I normally get on these short jaunts to work.

I get much lower gas mileage when it rains (3-4MPG in some cases). High levels of ethanol in the fuel will cause low mileage...

The FEH seems to get better mileage as one drives it... many have reported that around 5000 and 10000 miles the mileage seems to improve. Whether this is due to the engine or battery breaking in, or because the driver might be gaining skill in driving is fairly subjective. I myself saw this occur..... My mileage read approximately 24 when I started driving it in March, after 8,000 miles and mid summer I was regularly getting 29-30MPG (very close to EPA because mines a 4WD). Now that its Winter I'm finding my mileage is tending toward about 26-28 (and its been a very mild winter!!! mostly in the 40's).

Temperature seems to be a VERY strong contributor to the efficiency. From my admittedly very subjective observations it seems that on days where its over 50F I get into EV mode VERY quickly and my mileage tends toward 28-29... If I'm nearer to 40F EV mode is delayed significantly and my mileage tends toward the 26MPG end.

Tire pressure has a strong effect on MPG and when the temperature drops for winter, it has to be adjusted upwards to compensate as well. 35PSI in the summer I found was quite low when 40F comes around.

Its important to note that all cars will see effects like this (to a greater or lesser degree) and their EPA estimates will be incorrect.

I personally DON'T drive all that differently. My tires are at 35PSI, I don't P & G. I take it easy on the acceleration. I do let off the accelerator early and try to let the vehicle coast to the next stop.

These are some of the reasons one might not see EPA estimates... it is an estimate after all. Even the EPA has said that the technique used to create the number can be very inaccurate in real world situations on all vehicles and they are adjusting the technique.

I hope thats helpful and not combative....