Horrible Fuel Mileage

[TollKeeper]

Although I have a V8 with the 3.42 gears, mine averages 15-15.6 in the winter, and 16.6-17 summer. I have a pretty heavy foot as well. I dont really do any type of warm-up either, other than the time it takes for the garage door to open. When at work, I start her up, wait for the idle to come down a bit, maybe 10 secs, and drive off.

 

[NJTB]

Beacon, GMCman
Yes, I do let it warm up for a minute or two before driving, and am well aware of the loss of mileage in the winter months. I expect a loss of about 2-3 mpg when it's cold (below 40), this winter it just seems to be excessive.
It's supposed to go up to 60 today, hopefully won't have to deal with this much longer.

What's going on? Any news?

How long has the fuel mileage be bad? 4 or 5 months? How long do you idle before you start driving? I know some people in your climate will idle up to a half hour, so their car is nice and toasty before they start driving. I know this may not seem like much, but if you do that, then only drive 5 or 10 miles, it would drastically change your mpg.

 

[Tankcruiser]

could be the heater for 02 sensor might be bad or weak needs heat to operate properly just an thought