Poor MPG Suggestion: Air Con faults and Short Trips

[Phillip]

Hi ETCG,

Great resource here for fault finding of bad mileage. Thanks for that.

I’d like to suggest Air Con faults as another source of poor MPG to the Poor MPG FAQ.

My 2007 Toyota Previa (Tarago in Aus) was getting 17mpg with Air Con and 24mpg without. Not really acceptable for me because I use AC 3/4 of the year. It turns out the Air Con was overcharged with refrigerant, so when it was recharged properly the mileage was a more pleasing 23mpg.

Also, you didn’t mention poor mpg due to frequent short trips starting from cold. My mpg seems to be 20% worse when I’m only taking the car on 5-10 min trips and then resting for hours. The fuel gauge needle seems to drop fastest just after cold starts.

Topic

[EricTheCarGuy]

Thanks for the suggestion. Yes, anything that causes excess load on the engine will cause a drop in fuel economy. I believe I did mention that fuel mileage in the winter will go down. Partly because you warm up the vehicle, and partly because winter blend fuel is different than summer blend.

Thanks again.

[Author]

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