Loaner Camry Hybrid getting better economy than my Prius

OK, it's a 2008. Probably got it late spring or in the summer and for the first few months it was warm and the mileage was good. Then came winter, and mileage does tank. Mine averages 7 l/100 km in winter, sometimes even worse! But when summer comes again, it rises back up to 4.6 or so, and I also do a lot of short trips.

Did you just rent the Camry recently, during spring? That would do it. I'll bet your Prius will start getting good mileage now that it's warmer.

Note that short trips such as yours will result in mileage in the area of 4.8-5.5 l/100 km. The Govt. of Canada mileage numbers are nonsense. They didn't change the rating like the US EPA did, so they are -VERY- optimistic. I think I got what they say I should only once (4.0/4.1 is ridiculous, and requires warm temps, and very careful driving). But I can get in the 4.4s in summer if I don't short trip the car.

It's not the fuel. We don't use the US style winter fuel here. Currently only Husky/Mohawk has ethanol fuel (and I use it all the time without disastrous mileage hits). Make sure you put more pressure in the tires than the car info calls for. I use 40 PSI front and 38 PSI rear.

 

I think that you need to have someone investigate that first hand.

Not even driving on the autobahn and frequently examining the top speed got my fuel consumption up that high. At the moment, my commuting between my work place and my home (a mixture of city and highway) the average is 49 l/100km and this is with out even trying (using cruise control as often as possible, keeping pace with traffic and flooring it when I'm first in line at a stop light).

With that in mind, I have some questions:
The data you have, is it from the car or is it calculated at the pump? Does your speedometer display the correct speed?
Does the dash board warning lights work?

 

I drive like a maniac most of the time although the speed limit is the speed LIMIT, I waste no time getting up to it and I average about 4.3L/100km around town and 5.2L/100km on the highway at 110km/h but it's warm here, no snow ever.
Drive it like you stole it and see what happens to your mileage.

 

OP, I don't see where you've responded to oil level. Overfill is a common problem, and easy to check. I'm sure you've checked, but just asking.

If you get it warm on a pleasant day and your 5 min bars don't respond, then something's amiss with the car. The thread doesn't yet address your DROP in mpg, other than winter temps, which are a bear.

Consider a SG-II if you don't already have one, so you can monitor rpm, coolant temp, tps, etc. May provide clues.

 

Summarizing: dirty MAF, or overfilled oil, or tires too low. Go take a look.