there no light up will they still retrieve codes or anything without my check engine light on? the guy use to have a k&n drop in filter in it would that mess up the MAF any?

 

Yes it will , the oil from those junk filters can mess it up especially if the guy over oiled it...

 

Get rid of the k&n first, they are junk and do nothing. Give the MAF a good cleaning and replace the filter with a standard filter. My 07 E350 gets horrible mileage when the filter is getting clogged/dirty. The mileage seems right for your setup, changing gears may help a bit.

 

my truck gets about 14.5 highway, 10 city with 285's or my 305's doesnt matter. Also doesn't really seem to change if I have a load in it or not. Pretty consistant. It is a 5.4L regular cab with 4:10's. I did manage 17 highway once with the stock 235 85 16's but those tires were horrible performers on anything but dry pavement.

 

Why do people buy a 3/4 ton 4x4 truck with the smallest engine that's going to struggle even more with an auto, then proceed to install larger heavier tires (and probably wheels too). Then after all this genuinely act surprised and complain that the fuel economy sucks.

That'd be like me stepping out of the house in a pouring rain and >¥+{_ about getting wet.

 

Whats that nonsense about getting wet in the rain?

 

But the cheaper sale price for a gasser vs the higher sale price for diesel is suppose to make you feel better. Can't have it both ways.

Might be time to consider replacing the coil on plugs, "lucky" you only have 8 vs. 10

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The idea of a larger engine being more efficient in a heavier application is a complete myth. The idea that an engine is more efficient when it's not working hard isn't true unless you're turning higher RPMs to do it. Higher engine load at the same RPM is actually MORE efficient due to decreased pumping losses. This graph isn't for these specific engines, but the concept still applies: higher engine loading is more efficient, which is why overdrive gears exist:



I've seen dozens of people over the years who have gone from a V8 to a V10 and mentioned the loss of 1-2 MPGs. Allstar recovery would be the first to claim an increase.

The OP mentions 10.5 on the highway; how fast are you driving?

 

Tom. It's not a myth in all cases and your chart misses the point entirely.

We don't drive to a specific engine loading 99% of us drive to a specific acceleration rate. An engine that sees a lot of WOT (4cyl jeep anyone?) is for darn sure going to get worse mpg than one that can be operated in more leisurely manner.

Now I don't think a 5.4 SD is on the same end of the underpowered extreme as a 4cyl wrangler. But my point is folks buy these small engined trucks EXPECTING to get much better MPG. Compounding this is our current infatuation with putting heavy larger diameter tires on EVERYTHING these days, without regearing (nobody does) the bigger motor is absolutely better suited to maintaining whatever acceleration rate our driving habits dictate.

That -3 mpg for a v10 is NOT going to change the driving and ownership experience significantly to the negative. But that added power will definitely swing it to the positive.

 

It is true that there are pumping losses in a gas motor due to the throttle being partially closed in most situations. Generally a smaller engine will get better fuel economy, but you don't get something for nothing. In a big square vehicle air resistance is huge at highway speeds. Look up the EPA fuel economy ratings for the vehicles if you want to be sure.
For instance:
2004 F150 4.2l 14 city 17 highway
2004 F150 4.6l 13 city 17 highway
2004 F150 5.4l 11 city 15 highway

Of course the driver input can be the biggest variable. And if you really want to achieve the EPA highway ratings and exceed them you have to be on a lightly traveled highway where you can set the cruise and forget it. Bumper to bumper stop and go traffic doesn't count as highway driving. Even high speed driving on a busy highway in the city where you're off and on the gas won't get you to the EPA estimated fuel economy for highway.

Having looked up the EPA ratings I don't think there's anything wrong with the original poster's pickup. There are definitely improvements he can make, but 10 isn't out of the question, especially if his "highway" driving is on busy roads and his right foot is at all heavy.

2 cents.

 

Great analogy in my opinion.

I totally agree. You want great fuel economy buy a Fiesta, not an F-250 with extra large tires.

 

I personally think the OP has a slight issue. I'm rolling in a V-10 Excursion that's bigger/heavier than his truck on 35's. I'm getting 9-10 city and maybe 14 highway.

I think the OP can squeeze 1-2 mpg better. As mentioned, check brakes and all the fluids. Especially the fuel filter and air filter.

Best of luck. These things are gas hogs, but not always that bad.

Ty
2002 Excursion with some goodies

 

I have basically same truck except 255/85r16 tires and I have 4.30 gears and I'm getting 10mpg around town and 13 ish on the highway. I drive easy around town but I do smash the go pedal and highway is never over 70-75 mph

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Rims stock and tires came with it when I bought it. and struggle no I don't have much of a problem power wise its just 7-8 is kinda stupid it should atleast get over 10 plenty of other people do so theres proof im just complaining its not getting the standard mileage it should why cant I expect whats suppose to be standard for my truck. and hey buddy im only 22 its not like I need a 7.3 diesel i only bought a 3/4 ton because here and there ive needed one and put way to much weight in my 1/2 ton but its not all the time there is no reason for me to shell out money on a diesel when i don't need one i just need a standard truck that can haul a lot of weight occasionally when i need it too but mostly its light duty what do i need a v10 everyday for then? what do i need a diesel for then?

 

Let's pick this situation apart.

First off you're not really getting "bad" mileage for the truck. Yes you're on the low end but even if it was getting the EPA ratings it'd still be a gas hog.

Second the larger tires. I think all your. "Issues" begin and end with em. One potential issue right off the top of my head is has your speedometer been recalibrated? Taller tires have the vehicle traveling further than the odometer thinks it has and will automatically skew any mpg calculations to the bad side of things and gave you believing your mileage is much farther in the toilet than it really is.