how much gas are you putting in the tank at fill up?

[rathrbcruisin]

I have a 21 gallon tank and i'm usually putting 16.5 gallons in at fill up. The computer says I have 3 gallons left, which i'm sure is probably not exactly 3 gallons but probably close. do you think there may be 5 gallons left in the tank when it says 3? I had an issue with P0455 which ended up being the vapor canister had a hole in it. I blew the line going to the tank for the vent while replacing the canister to make sure it was not plugged. Air went into the tank, and then fumes and air came back out so i think that is ok. I also replaced the purge valve and the vapor canister solenoid. the main thing that makes me wonder if it is filling all the way is many times it drops off of full after 40-50 miles, then by 60-70 miles its on 3/4 tank already. usually i'm at 150 miles by 1/2 tank and fill up around 250-270 miles.

how many gallons are you putting in at fill up?

 

[Whityford]

Now I don't know about the V8's but I know that mine doesn't have a 21 gallon tank even though the manual says it has one. Mine is only the 17.5 gallon tank. Maybe it's different in between each engine and model? I think if you look on cars.com and enter the vin then it'll give you a more detailed look at your ex has.

 

[rathrbcruisin]

everything i've seen says i have a 21 gallon tank.

 

[sehaare]

everything i've seen says i have a 21 gallon tank.

Rock auto show 21 gal for replacement tanks as well

 

[lobo411]

Ford fuel gauges are usually wildly inaccurate.

 

[koda2000]

Depends on what size tank the truck has. Most of mine are around 20 gallons, some are only 17. If I'm filling a 20 gallon tank on level ground and the gauge shows 1/2 way full, it will take around 10 gallons, if I have 1/4 tank and park with the nose facing downhill it will read near empty. This is because the float for the fuel gauge is located in the rear of the tank. I've found that there are around 2 gallons remaining in the tank once it reads empty, but you wont be able to use it. The fuel gauge reading is estimate at best. I suggest you don't obsess about it and get gas when the gauge reads around 1/4 tank. As for as MPG, my trucks will vary between a low of 15 and a best of 22 MPG. There are many factors involved with MPG.

 

[1997XLTRollover]

Ford fuel gauges are usually wildly inaccurate.

I actually just chuckled a little bit. This right here is so true^

I've been driving nothing but Fords for the past 10-15 years and not one had an accurate fuel gauge lol. I'm talking Fords from the 60's 90's and 00's all the way to the newest being a 2012. None are super accurate.