Interesting Drop Off In Mileage

I just got only 225 miles out of 10.5 gallons of gas and I drive pretty easy - all city drivintg. 2004 CE auto with AC w/ 50k miles. I'm sure it's the extreme cold weather (average temp 15 - 20 f) but I didn't expect such an extreme drop-of. Lots of long warm ups and short trips don't help either.

In similar temps last week (single digits) my 95 Corolla MPG trailed off significantly but I still got 401 miles out of 12.9 gallons for 31 MPG.

I do not warm-up and have no short trips though. When you are warming up in extreme temps, the car takes a long time to warm-up to normal operating temps. During that time, the ECU is calling for a rich mixture to compensate for the feedback from the coolant temp sensor. When the oil light goes out, I get going. I also use full synthetic oil so cold starts are less stressful to my engine. I do take it easy with acceleration in these temps until it warms up just so undue strain is not put on the auto transmission.

As a comparison, hot weather driving will get me 39-40 MPG on the highway at 75 MPH.

Jay in MA

I just got only 225 miles out of 10.5 gallons of gas and I drive pretty easy - all city drivintg. 2004 CE auto with AC w/ 50k miles. I'm sure it's the extreme cold weather (average temp 15 - 20 f) but I didn't expect such an extreme drop-of. Lots of long warm ups and short trips don't help either.

That's 21.4 MPG. It is probably due to all the warm-ups and short trips. Generally you get zero miles per gallon when your engine is running and your car is not moving - such as during a warm-up or sitting in traffic.

 

With local temps in the sub-freezing zone, my gas mileage has been in the low 20's as well. I've also been doing a lot of warm-ups, so I expected the low mileage. However, on a recent 200 mile round trip to Maryland, I was getting my typical winter highway mileage of ~38 MPG. So, it's just a cold weather thing. Nothing to worry about.

On very cold days I start my car up, then go into the house until it is warm enough to drive.