All through winter our 05 Prius was giving poor mileage, so finally in spring I took the Prius to service. Explained my problem. I wanted to know if it was winter driving or something actually is wrong with the car. They did not find anything wrong. They dump a bottle in the gas tank to clear all cylinders. Mileage has gone up. Have you heard about this before? If so, how often we need to use this bottle to clear cylinders?
Coincidence?? You didn't specify actual mileage numbers, but mileage in winter will definitely be poorer than spring mileage. Provide some before and after numbers so people here can help you out better.
A cold winter day it dropped to 26 mpg, usually was giving around 36-38 mpg. Now after the clearing the cylinders with the fluid it has improved to 46-49.
Low temperatures reduce fuel economy in several ways. Many of these you cannot affect, but one you *can* affect is the tire pressure. You should check tire pressures at least monthly, or whenever the average temp changes by more than about 20'F. Reduced tire pressure can account for much of the MPG reduction you experienced.
My winter driving was in the 42-44 range. Now that temps have gone up and the gas has changed to summer fuel, i'm over 50mpg.
