[RSR100]

I have my 04 Prius since 9/04. I got great milage the first 2 months, then the red lights came on on the car went into Toyota for repair.
They told me the car just needed a software upgrade - which they did.
Since then my MPG dropped 20% from 42-48+ in town, and 45-52+ highway, TO 32-36 in town and 42-46 Highway.
I was told after I noticed the change that it wasn't the software change, it's the cold temps. Wait till spring. WELL it's spring!
SAME MPG!
I am going back to Toyota!
ANYONE HAVE THE SAME EXPERIENCE?
ROBERT

 

[DanMan32]

Rick over on PriusChat, who is a Toyota Master Tech, did mention that the 2nd to last calibration did take a big MPG hit. The last one seems to be a compromise, so see if there is a later calibration than the one you got.

 

[mrv]

with the temperature changes, and especially after a service visit, remember to check your tire pressures.

for every 10^F change in outside air temperature, your tire pressure will go in the same direction by 1psi. So, don't set your pressures on a warm day, and expect your tires to be the same when it drops 40^F in the next week or two. (Services are the worst - they'll measure your tire pressure in a warm garage, on warm (driven on) tires. IF they give you the factory 35psi front/33psi rear, by next morning (when tires are cold) your tire pressures are way too low...)

 

[ceric]

T vs psi

If my memory serves me correctly....
The absolute zero temperature is -273 *C (-459 *F). At room temperature, 27 *C, it is exactly 300 *C from absolute zero. In a fixed volume, the air pressure is proportional to the temperature. In other words, every 10 *C (celcius) increase in temperature, increase psi by 1/30=3.33%. For a 30psi tire, that is 1psi. In summary, every 10 *C change in temperature, the tire pressure changes by 1 psi (near room temperature).

My point is that you mentioned 10 *F ... I think it is 10 *C.
I could be wrong, though.

 

[The.Tramp]

Re: T vs psi

My point is that you mentioned 10 *F ... I think it is 10 *C.
I could be wrong, though.

18°F difference = 10°C difference.