Help! MPG suck!!
03-24-2017, 07:18 AM
#1
Help! MPG suck!!
I have a 2009 F150 with the 5.4 v8 engine. It is a lariat 4x4. For the past two years I have averaged 12mpg and I can't find the problem. It was leveled with 35's and I got 12mpg. I put itty bitty street tires on thinking it could be the big mud tires but still got 12. Now it's lifted 8in with 35s and still get 12. I've cleaned the MAF sensor, air filter, and changed 2 rear o2 sensors. The only time I had any success was when I took the throttle body off and cleaned it real good and inside. I put it back on and drove home from work. It jumped to 14.6. The next morning I drove to work and it fell back to 12. I have no clue what it could be. Someone help please.
03-24-2017, 09:37 AM
#4
Senior Member
There is a problem with the calculations somewhere. It's impossible to get the exact same MPGs with 35s as you do with stock 32s. Scientifically impossible.
I would full well expect 12 miles per gallon with 35" tires on a 5.4L equipped truck. But you should pick up 2-3 MPGs more with going back to stock equipment. I'd be looking at where the problem lies with your calculations first, then look at the truck if need be.
I would full well expect 12 miles per gallon with 35" tires on a 5.4L equipped truck. But you should pick up 2-3 MPGs more with going back to stock equipment. I'd be looking at where the problem lies with your calculations first, then look at the truck if need be.
03-24-2017, 09:51 AM
#5
Mark
iTrader: (1)
I get up to 14 MPG with 35's around town .. 3:73 gears
03-24-2017, 10:23 AM
#7
.. Your driving an 09 with a 5.4 12mpg if its cold out and well nevermind.. yeah 12 is ok
it sucks but what did you expect with a truck?
mine ranges anywhere from 17 to 12 depending on how Im driving and where and what its like outside..
it sucks but what did you expect with a truck?
mine ranges anywhere from 17 to 12 depending on how Im driving and where and what its like outside..
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03-24-2017, 10:27 AM
#8
Not an expert by any way - but if you don't recalibrate due to tire size, how do you know how far you have actually driven? And if you haven't re-geared, putting significantly larger tires on a vehicle will (IMO) drastically affect it's ability to work efficiently. Think trying to ride a bicycle using only the higher/more difficult gears. Same engine + higher gears = harder work. I know when I put 35's on my Jeep years ago, I didn't re-gear and it killed mileage and performance. Again, just my two cents...