No the HCH is not so sensitive.
This is not really what happened; her mileage didn not jump from 32 to 62 in a day.
She had never zeroed her trip meters.
They both showed the same number of miles as the odometer, 4600.

So, even though she may have been imporving her MPG recently she never saw it because each days MPGs were averaged with the other 4600 miles.

When I zeroed her trip meter it was the first time it had been zeroed.
She said she would zero one of them each morning now; that is the only way to compare MPG day to day.

 

whooo hoo! I got a 518 tank! Thank you Kenny!!!! You rock!!!!!!

 

I've had my 05 HCH for just over a month now, and was averaging 48.5 mpg on a 42 mile round trip via 80% freeway in CA. without using A/C. While I was happy with the average, I zeroed my B trip odometer Friday morning as I usually do, and lo and behold, averaged 62 mph!! A flaw, I thought, so I zeroed again today, Sunday, took a 40 mile trip on the freeway and averaged 69.5 mpg!! My car just hit 1,250 miles total. I really don't understand what's going on. I guess the only way I can really gauge what my average is, would be to empty my tank and monitor from a full tank. I would be estatic if the numbers worked out to be 60 mpg, but I'm totally skeptical. Most people say they see a difference at 2,000 miles. I'll keep you guys posted. I hope the hybrid faries aren't playing stupid games with my odometer!!!!

 

perhaps it is the 2000 miles point. i know that i just passed 2500, and since my last fill the computer has been showing 62 mpg consistently. and i have been driving both on the highway and on the slower backroads. i find it fascinating.

 

....spoke to soon. I reported unusual MPG over the weekend- up to 69.5 mpg! Well, Monday morning rolls around and it's gone back down to my usual 48 - 50 mpg. I think my car just hates going to my office!! It was nice while it lasted!!

 

I'm forming a theory that mileage you get in the first 1-2K miles of a new hybrid may be tainted by the tires wearing in. It's been discussed that new tires take a bit of wear to become efficient (this may be the cause of the ever-mysterious "break in period..."). I'm about ready to replace my tires - will check and report back what I find, now that my driving habits and route are a constant.

Also, don't be surprised at having 60-70 MPG trips every now and again, and then they disappear. The car provides so much feedback that it may do some harm as well as help. :-) For example...

I recently filled up a tank .5 miles into my 25 mile morning comute and zero'd out the trip odometer for the new tank. 25 miles of suburban and highway driving later I arrived at work with a record 70 on the display. Reason: there is a very slight, almost undetectable elevation drop from my home to where I work (I actually found a topographical map, as sick as I am...). Essentially, I'm traveling slightly downhill all the way to work (on that day, I also made about every traffic light, so the stars were truly aligned). On the way back, things averaged back to normal (you have to go back up). It could very well be the case that the 40 mile stretch you encountered was downhill. Or you had a tail wind - or someother explanation that you only are aware of because you drive a car with a lot of feedback.

After close to 45K miles I've learned to roll with it. I'm more interested in how I average in a season (winter, fall, etc.). Good and bad tanks (and individual trips) come and go, for reasons that can vary over a dozen variables (head wind or tail wind, rain or shine, road conditions, traffic, temperature, elevation, oil, tire pressure, did I hit all the lights, was I just spacing out or paying attention...) just to name a few. Endulge yourself in as much investigation and analysis as you find enjoyable.