Got my '06 F150 4.6l v8 4x4 2 door long box. Truck drives great feels great starts awesome. Bought it from my dad and he maintained it since new. He's a mecanic and used to own his own shop back in the day now he moved to Mexico. (6 months a year) Anyways, I realized today when I filled up I did 34 KM to get home and in that 34 KM, the fuel gauge dropped by like 5mm. Sounds like nothing, but this typical trip usually the gauge doesn't even move. I thought to myself maybe I was hardwr on the pedal. A week later, i realized my MPG dropped dramatically! A few commutes around town for a week required a fill up. I usually fill up once per 2 weeks (on the 1/4) now in 1 week I was 1/4 and actually drove less because I had 2 sick days off. Changed the fuel filter, did an oil change with High Mileage Mobile 1 5w-10 oil, new k&n oil filter, changed air filter to a k&n and added some fuel injection cleaner and octane booster to try and clean the system out maybe. No differance.

What else could be the issue? I drive really slow in specially these cold Canadian tempatures (-40c) and never hard on the pedal and 4x4 only use when I need it.

First Ford i've owned so not too fimiliar, I am use to Toyota a never ending truck lol.

Thanks in advance,

Daren

 

Cold air pickup clogged with snow? Animal nest in filter housing? Thermostat bad and engine running cold? Lots of possible reasons.

 

How many miles? Ever done a tune-up? Have you been letting it warm up for a long time?

 

Yes I recently (500km ago) did a a tune up. Change water pump, it was starting to go, changed the thermo it was still good but it was the original so I changed before it woulde, changed my plugs and wires because the truck just hit 200,000 KM and some othe minor things. I don't beleive their would be a nest in there because I use it everday. Looked for snowbuild up, nothing seems to be there. Right now it's in a heated garage incase to see if evething will melt.

 

I still let it warm up the same amount of time I usually do (10-15 minutes beausw at 5 AM to go to work its usually in the -42 zone) and its always plugged in. Inuse gas like antifreeze once a tank incase.

Could my tank vent be frozen (heard this is an issue) and just causing the gas gauge to think theirs less gas in the rank because of no pressure? Thanks again

 

You will have to calculate your actual mileage rather than going by the gauge. That method is meaningless in the technical sense. It could be simply the cold weather and extended idling causing increased fuel consumption.

 

just curious, have you checked for any stored codes at all during this process? sounds funny if your CEL isn't on but there could be codes stored that don't trigger the CEL that could adversly affecting the performance of the truck, I would see about pulling codes and also report any codes back for us to further assist with diagnosing the issue(s)

 

excessive idling could be the cause, but a good tune up should work. when i bought my 06 it got 13 mpg on the hwy, on a long trip. i put in a can of carbon cleaner, not sure the brand, i got it at my local napa. came in a metal can blue and read label. guy said it would help clean carbon from valves and such, didnt think it was going to work, but i put a whole can into a 1/4 tank of fuel, which is richer than advertized, after another tank it is getting 14 mpg around the city with 10 min idling everday. so as above calculate your kmpg with the odomoeter to comfirm what you are getting. the guage will read differently from an empty truck vrs one with 500kg in the bed. follow a valve cleaner with injector cleaner. hope it helps!!