Hey Guys I am having a issue with a 07 f150 I just bought
I am getting on average 8.0 miles to the gallon around 180 miles to the tank.

Yes I know this is a truck BUT this is the 4.6 STX model 2wd
this is city mileage. but the truck should be getting over 300 to the tank at least 13 to the gallon
its rated 15city and 20 highway

I took it to my dealer and informed them I have already replaced the boots <autolite> and the plugs <motorcraft platinum >
the truck isn't idling rough or missing that I can tell.

They claim to have done the following
Spark test,Compression test, fuel pump, fuel filter reset computer to insure it wasn't chipped. checked computer for codes they claim they have checked the computer as well
they claim there is no reason that the truck should be getting this bad mileage.

they are almost acting like they don't believe me. they want to fill the tank drive it 100 miles and refill it to test mileage that way

i don't really mind because that what i have been doing

But I need help figuring out whats causing this. they said they have called the advanced tech line as well.

I cant keep getting 8 miles to the gallon. Where as i knew it wasn't going to get excellent mileage I got better than this on my 90 bronco with a 5.4 and 4x4

I am also having the same issue on my wife's 2012 ford mustang v6 its averaging only 13 miles per gallon when rated at 19

let me ask you guys this as well they both came from the same dealer. same day purchase. Could the dealer have done something to the vehicles to make them seems like they have more hp but burn more gas, or cause them to run rich

 

Maybe keep your foot out of the pedal and not try to drag race @ every stop light? Check tire pressure?

 

How are you determining MPG? I was having issues where I was having to fill up every 200 miles or so when it used to be 350 miles. Turns out my odometer was borked.

 

The best way to calculate mpgs is by pencil and paper and dont rely on the dash displays...

The other thing is there stock sized tires on the truck or are they oversized?

Switch gas stations....might be something in the gas or bad gas....

Change the fuel filter, clean the throttle body, clean the maf sensor.....

 

Possible 02 sensor issues? f it was running in a continual rich mode, it would affect gas mileage, might also ruin your catalytic converters.

 

You aren't trying to use E-85 in them, are you?

 

The same issue on 2 different vehicles though? Either they are getting horrible quality gas, don't keep tire pressures checked, or are leadfoots. Or really bad at math.

 

When I was getting 8-9mpg, I took it to Ford and they diagnosed it to a bad catalytic converter. I swapped them out, and I jumped back up to 20mpgs.

 

Didn't see the part about the Mustang. Trying a different fuel station would be the first option in my mind.

 

I would go back to glc's question, are you trying to run E-85 in them?

 

I would blame the fuel in the tank. Don't know where you are at, but BP recalled over 1 million gallons of fuel.

 

ok will try to answer as many statements as possible.
I use my trip meter and then divide by gallons put in at fill up. i have topped off the tank and ran it to almost bone dry , fuel light on> and only got 190 miles city
I use regular gas usually from Sams club
as for the o2 sensor if it was bad wouldn't it be throwing a code. My computer is showing no codes. at lease that's what they say it the dealer
I dont have a heavy foot. Yes my wife does but I dont.

the dealer filled the tank themselves, drove it then filled with gas. they claim they got 16 highway. But in a 4.6 shouldn't I be getting better? its rated that for city

they have no idea why I am getting such bad mileage in town and honestly feels like they don't believe me

 

Quit using Sam's Club gasoline for one. Secondly, the bad O2 sensors don't always throw codes.

 

sams gas is bad... I try and avoid it and i do a good job with it. My grandmother noticed a 1-2 mpg difference between the E-10 sams gas and the E-10 Casey's gas. Casey's being the better in this arguement. i saw a 2-3 between Casey's and BP on E-10.

 

so how will i know if the o2 is bad. and i usually use them or pilot for gas in th epast I can switch back to pilot.
any other ideas. and how many fuel filters are there on this truck one at the drivers door i know but is there another?
and whats the location of the o2 is it hard to get to