Colder weather has zapped my mileage to 44mpg

23!!!! WOW... that's really bad. So, did your gen 2 MPG use to plunge like that during winters? Maybe gen 3 is even worse? It was supposed to be better...

 

Need more detail. Your Gen III got 45 mpg and now gets 23 mpg? What is your tire pressure? Any vibration or pull noticeable? From a typical cold start, how far are you driving? Still on initial motor oil? Where is the oil level on the dipstick? What mileage did your gen1 and gen2 get, and has anything changed in your driving? When did your mileage drop? Did anything else happen to the car or your driving or the weather around the same time? Do you have a scanguage?

 

doxie53, these are really good questions that need a detailed answer for help...

Welcome to the trouble (my opinion) of finding out what is wrong with this car in the winter...

 

23mpg isn't bad "winter" mileage - it's bad mileage, period. Something MAJOR has to be wrong to get those numbers - check for a flat tire.

 

Indy - your mph/mpg chart has a suspicious bump at 66-67mph. That's what I meant by resonance. Do you feel any vibration whatsoever above or below that speed? It's really strange that you'd get better mileage at 66-67 than at 60-65, and I would suspect a balance issue with one (or more) of your tires.

 

withdrawn - ot

 

I just wanted to check what the result of grouping MPHs and Temperature over MPG was, so I did not consider other factors like rain, snow, cargo weight, etc... It may just be that my trips at 60-65 MPH had more adverse conditions compared to the ones at 66-67 MPH. But I did find interesting that regardless of the presence of adverse conditions randomized among all trips, the temperature effects on MPG resulted in a nice chart, which suggest that indeed temperature is not only the most important factor but also the one less influenced by other adverse conditions. Does that make sense?

But I do plan to align my Prius in my next visit to the dealer at 20K, which is in about one month... I feel no vibrations at any speed though.

 

If you have to maintain a log for tax or per diem purposes, please consider using a trip meter, say B, for something like this:

	Column 1	Column 2	Column 3	Column 4	Column 5	Column 6	Column 7	Column 8	Column 9
0	date	purpose of trip	tax	miles	MPG	avg mpg	F(or C	dry	head winds
1	yyyy mm/dd	visit client to discuss business	Y	999.9	99.9	99	-10F	Y	+10

* estimate headwinds based on flags and speed

The second and third columns are not needed here, save them for the tax or expense account. Someone more knowledgeable about tax records might be able identify if start and stop locations are needed. For us, these would help us understand the altitude changes. We're mostly interested in getting detailed records that can be used for multi-variable analysis.

Bob Wilson

 

I have noticed the same drop in mileage with the cold weather ...I experimented by using the power mode and driving within the eco range, trying to avoid going into the red zone ...seems to make a difference in performance and milage over just eco mode ...any one else try this?

 

I'm so amused by all the complaining that I can't wait to see how people react when we finally have vehicles that get 200mpg and they see their MPG drop 15% and they lose 30mpg! Hahaha

 

If it is a Prius making 200 MPG, it would actually loose up to 60 MPG... hehehe....

 

LMAO!

 

I'll risk being chastised and admit that I've just bumped my fuel grade from Shell-87 to Shell-89 a couple of days ago for the first time this winter in an effort to try and combat the fuel economy drop resulting from the colder weather.

So far it's looking considerably better with 89; the engine seems to be lugging less at lower speeds (the low-pitched exhaust sound that was occurring while gently accelerating in the low 1280 - 1350 RPM range is mostly gone), and the fuel economy is currently reporting better by more than 10% from 4.5L/100km (52 mpg) on the previous tank -> 3.9L/100km (60 mpg) for the two days that I've been running the 89 fuel (note that it's not really this good since my car reports better fuel economy than it delivers -- by as much as 10%). Anyway, it's definitely too early to tell how things will end up, at least from a fuel economy perspective, since it takes me about two weeks to go through a tank of gas.

I tried Shell-91 once last summer and got one of my best tanks (3.5L/100km or 66mpg, measured) with it, so I thought it might be reasonable to try something like that again in the winter -- just to see what would happen.

 

In WI, Shell pumps display a sticker indicating 10% ethanol in their 87 grade, less in the 89, and no ethanol in 91 grade, so, most likely, the better FE comes from less ethanol. Apart from the ethanol content, I believe the difference in FE between grades is negligible in cars like the Prius, but hopefully the Prius chatters experts will chime in and educate us...

 

Looking forward to the big January thaw in the midwest... it will most definitively improve my MPG... temperatures are supposed to stay considerably above average for 10-15 days, which means at least 4 long trips for me!

 

And you know the "no rattles" and "good reliability" because... ?

Let's see how the Prius and A3 have stacked up so far in the reliability and squeaks and rattles department.

 

Since you brought up the EPA estimate, please consult the articles and URLs in my post at http://priuschat.com/forums/other-c...uth-about-epa-city-highway-mpg-estimates.html. I brought them up earlier in the thread.

Let me get this straight. Manufacturers (and presumably dealers) can only legally advertise EPA numbers, so you want them to go and advertise lower numbers, outside of this? And/or, you expect Toyota and other hybrid makers to go to the EPA to get them to add yet another test cycle or adjustment/correction that reflects lower temperatures and your 75 mph+ driving because some models/classes of vehicles get hit worse in something not reflected in their test?

Please consult my post I pointed to above. You'll notice that in none of the test schedules is the average speed higher than 48.4 mph.

 

The only 2 things I have bought following CR were my worst toys ever. Many people agree CR is so inconsistent and faulty, but I admit it roughly helps to provide a big picture idea.

Go back and look at your CR table under audio system from 2004 to 2009. We are talking about Priuses from the same generation (2), and yet the ratings vary from the better to the worse? How different could they be in the same generation? CR has to be evaluated with extreme caution and my experience confirms that!

Now, how about this: My colleague just next door to my office has a gen 2 Prius. She thinks it is just OK and she warned me about 2 big issues: bloody rattles and winter MPG drop. My brother and my best friend have A3s, not the TDI but gas powered. OMG, the ride quality is so nice and after 3 years for both, rattles are ZERO. In fact, rattles is just something my brother never experienced after 4-5 Audis in the past years. Why should I even pay attention to something so questionable like CR in this case? No way.

Regarding reliability... OK, I admit that Toyota does have better reliability than Audi overall, and the Prius is likely considerably more reliable than the A3. Fine, but so what? I still think that driving a decent, solid, and comfortable FE car has to have some price associated with it, I just wished the price was not: poor interior quality and poor FE in the winter.

 

My goodness, we beat this to death already but let me clue you in:

I'm careless about how the EPA test is conducted. What I do care is that beating EPA estimates has always been so bloody easy in any of my past cars regardless of the speed or air temperature, except in the Prius! Ring a bell?