Poor MPG also Does your Indicator wiggle?

Have you answered http://priuschat.com/forums/gen-iii...-answer-these-questions-esp-if-youre-new.html in any of your threads yet?

You might not be able to achieve much better given your trip lengths and weather conditions. As I posted elsewhere, consider:
- grille blocking
- better heater usage. By better, I mean don't use auto and set the heat to but fan to off when stopped or driving at low speeds. This prevents the ICE from running to provide cabin heat, further hurting your mileage.
- engine block heater, but that's a lot more $ than blocking the grille.

 

Your biggest problem I can see from that message is going 67 or 68 mph, the Prius, like all normal cars, get less gas mileage the faster you go. If you cut that speed down to 55 and you go far enough, you could easily get over 50mpg. I'm not willing to go that slow, so I average 45mpg. (calculated)

The V with it's bigger 17" wheels doesn't get quite the gas mileage as the ones with normal 15" wheels, and to expect the same is just not realistic. (even though the EPA doesn't make a distinction.)

And yes, the gas mileage gauge wiggles, things change on the road all the time that effect that. Wind, surface differences, inclines, ...

 

If your description of your increased tire pressures is correct you have the pressure variation backwards - the higher pressure should be in the front tires (door sticker advises 2 pounds more in front than in back).

 

Study the thread/page links in my signature...

I learn something each time I review them.

 

I was getting roughly the same mileage in my 2010 V...around 37-39. The temps were in the teens. I increased my tire pressure to 40/38, and blocked the lower grill 100% (haven't blocked any of the upper yet), and my mileage has increased to roughly 41-42. I think it could be closer to 45, but we've had a bunch of snow and muck on the ground over the last tank of gas, so until I have a period of time with no muck on the ground (at this point it looks like we'll be well in to August), I won't have any better numbers. But, the tire pressure, grill blocking technique, cabin hvac mgmt, along with pulse/glide work. I also purchased a Scangauge II to get a better idea of what was/is going on under the hood. This has also helped quite a bit...plus, it's a neat toy.

 

Even going 67-68, I would expect a little higher than 37-39mpg. My daily drive is 5 miles, and I get in the low 40s. It sounds like he has a pretty reasonable commute, given his comment of 5-7 mins regarding the cruise control.

It's well known that high speed means lower MPG, but I've also done some "mountain" driving at 75 and gotten 45-48 MPG during winter.

I think grill block is a good first step. Definitely answer the questionaire from cwerdna, too. Heater control is also a big player in the MPG during winter. I keep mine set to 68, and try my darndest not to even turn it on (easier to do with only a 5 mile commute, though). Even when I do turn it on, I manually control the fan and keep the fan speed below 3 bars (unless others are in the car). I also wait until I feel the engine may be warmed up a little bit. If I come to a stop and the engine isn't fully warmed up, I'll turn off the heater until I start moving again.

 

15" wheels? Makes a difference...

 

I'm averaging 39 mpg and that's an 'improvement' over the 34 - 37 I was getting before. Temps here are around 45 degrees right now. I'm concentrating on keeping the HSI indicator under the center line, as much as possible. Short commute of 6 mi each way. I studied the video someone posted, which was very helpful to understand this pulse 'n glide technique. I bet one of these days I'll get this car to average 40mpg! I increased tire pressure but it's time to check it again.

 

I should clarify regarding the heater usage. Once it's the ICE is warmed up, you won't need to worry about the fan off, as much. Unfortunately w/o something like ScanGaugeII - Trip Computers + Digital Gauges + Scan Tool, you have little idea when the ICE might run to provided requested cabin heat.

On the 2nd gen, if FWT (Fahrenheit Water Temp) is <=146 F, heat is at HI and fan is on, the ICE will run. So, if I see the FWT falling to 146 and I'm stopped, I shut the fan off.

IIRC, john1701a stated that on the 3rd gen, if you use eco mode, it'll prevent the ICE from running to provide cabin heat until FWT is down to 110 F. I have no means of verifying.