Getting pissed about mpg in 5.0

[Big Slick]

Okay, I am starting to get pissed about my mpg in my '11 5.0 s-crew 4x4. I keep reading how people are getting 15mpg city. I'm steadily dropping and currently at 12.6.

I put in a K&N intake
I drive 90% city and my commutes are between 10-15 minutes long to and from work.
My tire pressure is at 37lbs on all 4.
I use regular gas
I drive under the speed limit more often than over.
I accelerate slowly and coast often.
I have not tried any fuel injector cleaner but was going to pick up a bottle for my next fill up.
I have a tonneau cover covering the bed

What the hell is going on? Why am I getting such crap mpg? What else should I do/check?

[Jersey_Joe]

I've always burned 89 or better and I use zmax every 6,000 miles. Give it a **** and see how u do bud

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I wrote shot. Guess it spell checked ish. Lol

[baldyman]

your k&n might actually be part of the problem too. I believe it was Rhino that made a point on here saying that city driving and a k&n don't mix well. this is because when you're driving city the k&n is effectively sucking hot air from under your hood into the throttle.

unless of course you have a closed-box k&n lol

[BFEB]

Aside from driving style I'm not sure what the difference is. I'm sitting at 14.4 on mine and all but 50 of the 500 miles I have are all city.
You might try letting the truck do its thing and just set the cruise on any long straights you have. I set my cruise right at the speed limit everywhere I go.
I also don't think the K&N is the issue. My Airaid is open and not that I have something to compare it to, but I really think there is no difference in MPG with or without it for my commute which is about 10 min.

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Another thought is have you reset the MPG meter? Maybe try taking a 25-30 mile trip down the highway and see how she does with that.

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Another thing you may try is putting the LCD in the mode that shows all the software info. That area has a lifetime mpg meter

To get into that mode put in your key, hold the OK in the middle of the d-pad, then turn the key to on without starting the truck, wait for the built Ford tough screen to go away then start her on up. Just press the OK button to change what is displayed and hold OK to get back to the typical mode.

[RhinoZ24]

Also try calculating your MPG's yourself, computers are off a little. Clean the throttle body, use the ZMax Joe said, it's expensive but it'll clean your engine pretty well, and the tonneau cover has been said to actually reduce instead of increase mpg. But I've heard mixed results about that.

[BFEB]

U still stuck on that tonneau hurting mileage kick? Lol
I can tell you first hand that I gained 0.5 - 1.0 mpg hwy when I put mine on the EB. No difference in city mileage to speak if with it, but it really doesn't get a chance to do its thing in stop n go

[RhinoZ24]

Like I said, I've heard mixed results.

[iH8chevy]

I use 91 chevron and get about 340 360 in city with my 5.4l aftermarket tires no lift

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Over 400 highway too k&n flow master oh flex fuel too !!!f150 2010!

[Raptor05121]

OP, I would take off the K&N and do a controlled run with it and one without it. I cannot imagine an intake would make much of a difference, but it wouldn't hurt to check and see.

Secondly, how many miles do you have on your truck? Is it past break-in? The first 5,000 miles you should be varying the engine speed and break in the piston rings. The engine also helps by holding open loop for longer and running its stoichiometry at a higher percentage (thus lower mileage) until it is properly broken it.

Don't bother with any fuel injector cleaner. You'll risk ruining something more than it will helping. Shell and BP gasoline have been proven to keep an engine cleaner than one with cheap fuel and fuel detergents.

Also try calculating your MPG's yourself, computers are off a little. Clean the throttle body, use the ZMax Joe said, it's expensive but it'll clean your engine pretty well, and the tonneau cover has been said to actually reduce instead of increase mpg. But I've heard mixed results about that.

New engines have a coating on the inside of the throttle body and intake manifold, so it is advised to take it to the dealer and have them use their BG vacuum system to safety remove contaminates. BUT, given the fact his truck is too new to accumulate any carbon buildup, I would give it at least a year or two before you worry about it.

I use 91 chevron and get about 340 360 in city with my 5.4l aftermarket tires no lift

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Over 400 highway too k&n flow master oh flex fuel too !!!f150 2010!

Why are you using 91 octane? Your truck calls for 87....

[RhinoZ24]

OP, I would take off the K&N and do a controlled run with it and one without it. I cannot imagine an intake would make much of a difference, but it wouldn't hurt to check and see.

Secondly, how many miles do you have on your truck? Is it past break-in? The first 5,000 miles you should be varying the engine speed and break in the piston rings. The engine also helps by holding open loop for longer and running its stoichiometry at a higher percentage (thus lower mileage) until it is properly broken it.

Don't bother with any fuel injector cleaner. You'll risk ruining something more than it will helping. Shell and BP gasoline have been proven to keep an engine cleaner than one with cheap fuel and fuel detergents.

New engines have a coating on the inside of the throttle body and intake manifold, so it is advised to take it to the dealer and have them use their BG vacuum system to safety remove contaminates. BUT, given the fact his truck is too new to accumulate any carbon buildup, I would give it at least a year or two before you worry about it.

Why are you using 91 octane? Your truck calls for 87....

His truck is a 2011 and he bought it used lol. That's why I said try cleaning those and using the fuel system cleaner. His engine is definitely past break-in lol. I was, however, unaware of the coating on the tb and intake manifold.