Do you want more air flowing through your intake?

[adollarwodbnice]

I am definitely going to see if mine is broken..., you said they break after 10 years? Well my 850 is 14 years old and it gets pretty crappy gas mileage especially when i'm spending 40 bucks to fill the tank and only getting about 330 to the tank....

Could it be possible it's stuck on the cold side and when it needs warmer air to run better it's receiving cold air? I don't really understand how it works..., i'm just trying to figure out how to get this car to get better gas mileage.

[tjts1]

I do this modification to every volvo as soon as I get my hands on it now. I don't know what the mileage was like before, but this 5 speed 855 with 171k miles has averaged 25mpg over 3 fill ups in mostly city and some highway driving using 87 octane. I have seen 380 miles on a tank in this car and the low fuel light hadn't come on. I love the huge fuel tank. Here in Northern California we are paying $3.49 for regular.
The easy way to check is to remove the air filter after driving the car with the engine warmed up and stick your hand in the bottom of the airbox. You'll be able to feel which way the door is pointing.
I don't see how cold air could hurt fuel economy. This device was a cheap way for volvo to meet startup emissions requirement. On the other hand forcing the engine to breath hot air thorough a straw will hurt fuel economy and increase octane requirement. It also tends to overheat and kill the AMM sensor at the top of the airbox.