According to my owners manual for my 1999 5.4L F-150, I have a 32-gallon tank. Yet, if I run it to below empty marker, and fill it up at the gas station I can only pack in about 21.20324 gallons or so. And off those 21.20324 gallons Im only getting about 240 miles. My truck is not stock, and the only thing that noticeably affected MPG was the shorty headers. SO my question is, for my year range Ford owners, How many miles per tank are you pulling?

 

i pull 13 with a blower on top in break in miles.
btw, you should have a 25 gal tank with a 5.4?

 

I have a 1999 F150 5.4L Lariat 4wd. I get 300+ miles on a tank and then the fuel light comes on.

Larry.

 

yea you must have misread...weve got 25 gallon tanks man and ive got a 4.6 and get about 17 but my dad has the 5.4 and he gets 15..but thats a 43 year old man drivin that drives like a old man haha lol...sooo idk what the deal is...you might need some motor tune up work done on that thing..that should help out a little

 

you cant rely on the gas gauge in these trucks. if nothing else it could be things like your fuel filter, spark plugs, cop's, intake, etc.

 

What I can't believe is the better mileage I'm getting running High Test. I thought that " 94 Octane will get you better economy and performance " was a stupid myth until that poster from two weeks ago swore he was getting better mileage..

Reports suggest "The false belief syndrome" -

Well, I ran some premium in her and she did perk up a bit - sort of a different sound coming out of that pipe in the back as well.

I'm not sure about mileage - This tank full is a wash, to much fun with that new sound - so it wouldn't be fair to average mileage. I'm going to check that next round.

I ran 305 miles on the e-way 3 weeks ago - non stop on Regular Petrol. Finally filled her back up @ 364 miles a few days later. I went about 355 before the light came on. Mostly all e - way miles.

 

so jbrew your sayin with 94 octane your gettin more performance and economy outta it...so is it worth the extra 20 cents a ********** gallon for it...all we have where im from is 93 octane and its about ohh 4.20 a gallon

 

... yeah i dont estimate my mileage anymore to see how good im doing... i just do it to see how heavy my foot was last week.

 

Nope, I didn't say that. I believe in opposite and usually would give the guy hell for even posting that, but she does sound different. More like that GT 5.0 -That High Test slow burn effect. Actually High octane is a more efficient fuel and does burn slower - That's the facts of it -BUT, in most applications this doesn't improve anything worth spouting off about. I said MOST applications. I’ll see for myself where the 5.4L fits in. I haven't tried for mileage yet. Shoot , you put the coals to the 5.4 just once and you can forget about gettin any increase in mileage out of that tank.

Sunoco specs are the highest I believe. If you have one , you'll find 94 Oct.94 runs 4.39 + / TurboBlue = 7.70

 

I tried the 93 in my 4.6 for a few months. It seemed to get better mileage for about a month, and, then went back to the way it was previously. My guess is, the PCM finally adjusted to the octain.

I don't use 87 due to detonation. So, mid grade is what I run. I get 380 miles out of my 25 gallon tank before the light kicks on. I have about 180k on the clock.

 

The only F150's that had larger gas tanks are the long beds.. If you have a long bed, then you have a larger tank.. Otherwise, it's a 25 gallon one.

I've not run mine below 1/4 tank for some time, but I do remember running it to the low fuel light coming on when I first got it and it took about 23 gallons to fill up. I did that so I'd have a general idea of what I had left when the light came on.

Now a days, I fill up once a week or around 230 miles and just under 1/2 tank.. I try to keep my truck at no less then 1/2 tank if I can help it.. Just makes it easier to cope with a $60 'fillup', then a $95 'fillup'!

Over the last 7 years of driving this truck, if I get 100 miles to the first 1/4 mark and 200 miles to the 1/2 mark, I know I'm right on my ave mpg range of 15-16 mpg... If I do let it go to the lower 3/4 mark, I'm at around 275 miles...

Mitch