fuel mileage in the crapper

[Rjstepp]

So far on this tank I am at about 90 miles and 1/3 of a tank used, 38 gallon tank, so roughly about 13-14 gallons over that time or 6 mpg. Now performance is normal and I have no codes per my edge. It did it a couple weeks back and then came to on the lower half of the tank, to around normal. Did the blue spring mod today(I know this shouldn't help) and had the secondary filter out, it to me looked ok, although it was a carquest one and not motorcraft, but thats what it had in it when I bought it. The filters are going to get changed out this weekend or next depending on funds, just trying to get an idea of why the mileage falls so bad but performace does not

[Aussiekeeper]

Winter fuel? Warming up engine before driving?

[TMAG6.0]

6mpg??? Hole in tank?? Seriously, its not on the ground right? What was your mileage before the tune?

[Rjstepp]

Originally Posted by TMAG6.0

6mpg??? Hole in tank?? Seriously, its not on the ground right? What was your mileage before the tune?

Mileage before tune was around 12 city/ back country roads and highway unknown before tune After tune was mid to high 13 and around 17 highway. Did it a couple of weeks ago but bottom have of tank leveled out to around 12, which I would figure to be about right seeing as winter diesel. No holes in tank that I have noticed, and you would think I would notice that much diesel leaking, I always look under my truck whenever I come out from somewhere. Only other thing that I could think of is someone siphening fuel out of tank seeing as I don't have a locking fuel cap

[dazdillenger]

check to see if the clamps are on the filler neck at the tank-if someone is siphoning, that's the easiest way to do it. Other than that, check your oil-If you're consuming that much fuel with minimal smoke, It's going somewhere-is the oil overfull?

[DELTAJOHN]

Something is wrong...................I easily get over 200 miles out of my first 1/4 tank of my 38 gallon tank. My average is 18-19..........20-22 hwy unloaded.

John

[U235a4]

Originally Posted by DELTAJOHN

Something is wrong...................I easily get over 200 miles out of my first 1/4 tank of my 38 gallon tank. My average is 18-19..........20-22 hwy unloaded.

John

what year truck and strat?