S40 Trip Computer Current Fuel Consumption Problem
 

The "Current Fuel Consumption" (can also read "Instantaneous") indicator on my S40 Volvo seems to be problematic. The fuel consumption indicated seems to be all over the place, some times reading as high as 45 - 50. Even when stationery it can read 12. What causes this and is it something I should be concerned with. I do not seem to be using excessive fuel and the other indicators, "Average Fuel Consumtion", seem to be working fine.

That's normal. Your instantaneous fuel consumption in a modern car is nowhere near constant. When coasting on the brake, you will often use no fuel as the motion of the car keeps the engine turning. When accelerating it will drop down to just a few MPG. Mine varies anywhere from 6-99MPG in stop-and-go driving. The average consumption is a much better measure of the engine efficiency.

Thanks. That's is good news. I was worried something was about to go wrong.

The thing about the instant reading is to show you what your getting at the moment. The trick or goal is to keep that number as high as possible at all times. You can turn it into a game and increase your average mileage as high as 20%.

It can help a lot in learning to have a light foot - you can learn how little throttle is needed to maintain a given speed and easily gain 3-4 MPG.

Just remember to look up at the road occasionally!