Ok, so I know theres a million people bitching that theyre geting bad mileage but heres mine anyways! My 04 f150 subercab fx4 w/ 5.4l got about 300 miles to a tank in the summer when I bought it. Now, its doing terrible. The light turns on at about 235-240. Its driving me nuts. Ive even tried premium and driving like an old man and it does nothing. Is there really such thing as winter gas and if so can it mess my mileage up that bad?

 

How many miles do you have and what maintenance have you done?

 

The truck only has 35,000 miles and is in mint condition. Reg oil changes, has k&n drop in filter, custom exhaust. I baby it. Its like the bad mileage came outta nowhere. I put in a bottle of stp fuel injector cleaner today. Could it need plugs? The only thing i can think of is that in dec i had to have the air intake manifolds replaced. Cost me $700! But it was getting bad mileage before that and still is.

 

Have you always had the big tires on ? Takes more energy to turn em!
I've noticed a drop in my milage as well during winter, 19.35mpg highway at 100 on cruz x35 gal. (135 liters) = 677.25 miles approx Last summer I had one trip I got 23.5 mpg. only mods is, I use Bi-Tron additives

 

That pic is actually my old truck. I traded it in a while ago and i guess i havent taken the pic off. The new truck has normal goodyear tires on it. Actually theyre all brand new, and theyre the correct size.

 

It just makes no sense to me. If anything, i drive the truck more carefully now to try to get better mileage. I dont see how i can go from getting 300 miles to a tank to 240 when nothing went wrong with the truck!

 

Could be winter blend plus you probably let it idle more in cold weather to warm up

 

I will admit, i did have an auto start put in in dec and i use it every morning before work, but it only runs for abt 5 min or so before i get in and go. Could that make that much of a difference in mileage? Also, what exactly is winter gas?

 

So you haven't done any maintenance besides engine oil? It's time to change your diff fluid, trans fluid, fuel filter and switch to 0w-20 or 30 oil with a good filter like a Wix or Mobile 1. I'd switch to a dry air filter as well. What gears do you have and what size tires?

 

The remote start hurts it more than what people think it does IMO. I've been letting my truck run about 5 min before I go to work of a morning and my mileage has dropped from 16-17 around town to 14. Honestly if I were you and my truck was only getting 240 to a tank I'd be either calling the police to investigate the siphoning of fuel from your truck or be checking for a serious fuel leak. That's ridiculous. Even 300 to a tank is only 10 mpg for me. Of course I'm talking a 30 gallon tank here too so depending on your tank size your numbers may vary. Change your fuel filter and run a good quality fuel system treatment every 2500-3000 miles. Also run good gas from a quality station. Someone on here recommended me to www.toptiergas.com. Look over those suppliers and trust me it's helped my mileage. I never run anything more than 87 octane unless I'm pulling a trailer. Maybe you could have a MAF sensor going bad or something similar.

 

My 1997 F150 4x4 with 4.6 gets around 19 sometimes 20 mpg during the summer on the highway. With the cold temps here in Michigan during winter I am now getting around 12 city and 15 highway. Always has. I don't even use a remote starter. This truck and vertually everyone elses that I know (all brands) get considerably less mileage during the cold winter months. Tires, bearings, oil, Transmission, everything gets tight when cold and takes more energy to move. Your remote starter hurts your gas mileage more than you think. When I'm upnorth driving in 4x4 through 2 feet of snow I don't even want to know how that affects my mileage....All the extra front components the engine has to move plus the resistance of the snow sucks gas big time! When summer returns so will your mileage.

 

I'm thinking I'm down 2 to 3 mpg in winter

 

i have an 08 FX4 SCREW and I was getting about 14mpg in the summer, and now i get about 12.5 - 13 mpg... i never tested the mileage before my AIRAID cold air intake, but I did put the Flowmaster 50 SIDO on this past fall... and I noticed it actually went down at first (when I had it straight piped i was getting 12 mpg), but once everything was installed back up some, but only to like 12.5-13mpg... so I dunno, I've never gotten better than 16 even on the highway in the summer... my mileage stinks, so I dunno what's up.... I'm not necessarily complaining about mine, I'd rather drive my truck than a car, I just wish I could do something to get better mileage too...Oh and Im down here in North Carolina, so it's not way too cold or anything durring the winter, but I guess the fluids being cold could have some effect. 1 more - I never let my truck warm up, i just get in it and go, but I do keep it in a garage, don't know if that helps much...

 

heck i get 400 miles a tank city driving on my 03 with a 25 gallon tank. Got as much as 430 on a trip . I average 15-16 city and right at 17 on the highway. Guess them 2V motors are a little better gas savers

 

I just bought a 2005 SCREW 4x4 with the 5.4. It has 2" lift front and rear and has a pretty aggresive tread pattern Toyo 275/70-18. I am LUCKY if I get 11.5 mixed according to the onboard comp. I have not had it on a highway run yet. My 2007 150 2wd with 4.6 averaged 14-16 mixed and 18.5 Hwy. If my new truck doesn't improve A LOT I might just poop my pants. Oh and it only has 27k miles.