when driving in winter, i was getting 20 mpg in the summer, went to 16 mpg, then recently 12, and now i am only getting 60 miles per half tank or 120 miles per tank, i am planning on doing a tuneup but was wondering how much everybody elses fuel milage dropped off. if it matter the doors got locked and the engine idled for 2 hours a week or two ago, wondering if it maybe took out the o2 sensor?


92 f150 2wd 4.9

 

I'm running about 10 (give or take a bit; I'm looking more for ballpark than precise to the seventeenth decimal) in a '92 F250/351/E4OD/4.10 Super Cab. I have had some problems with it the past week or so, though; the TPS looks like it's intermittent and I disconnected the battery while troubleshooting a no-start this past weekend, plus I had to fill it with gasohol and am running that out. (During the TPS phase I was getting 7.3, so I'm quite happy with 10.)

 

When the truck is idling it is getting ZERO miles per gallon, so yes it does matter

 

I expect a pretty big decline in fuel mileage in winter. My F250 only gets 8 making all the short trips it does. My Focus (that got 45MPG all summer) only gets 29MPG now.

I wouldn't let those numbers bother you too much unless your engine light comes on, or the problem doesn't improve when it warms up.

Call a doctor if the problem persists after 4 hours though.

 

I don't check mileage unless its a highway trip. In town I'd rather not know, probably single digits with warm-up & short trips. Highway is usually ~17 in summer, that drops to ~14 on a good day in winter. Remember, not only is it colder & you do warm-ups, but the fuel isn't the same either. They use the shorter hydrocarbon chains (the lighter ends) in winter to keep volatility at ambient temperature to an acceptable level.

 

I cant say I've noticed a change in mileage at all during the winter... though our winters are pretty mild out west