Hey guys, just thought I'd throw this out there with probably more info than is relevant or necessary...

My truck is a 2014 F150 FX4, has ~6600 miles on it at the moment, and is leveled. Other than that, it's stock.

Just a side note, I saw on one of the tuner's websites or videos or something that just by switching to premium fuel, the truck gained 8hp over regular fuel on the stock tune, so I ran the last few tanks as well as the current tank with premium just to see if there would be an mpg increase, but I got no such luck.

So, when the truck was completely stock, I took off the front lower spoiler just because I didn't like the looks, but went from mid 17 to low 18 for mpg down to mid 15 to low 16. Put it back on shortly after. Then the truck was leveled, mpg went down to low to mid 16. Just recently, I removed the running boards just because but I doubt that had much to do with it, and I also removed the front lower spoiler again. Currently I'm sitting around where I usually like to fill the tank which is between 1/4 and 1/2, and my mpg 17.6 as I just parked it, and that's going completely off of the in dash fuel economy.

The only logic I can think of is that the lower spoiler is designed to work at the factory height/stance, and that was ruined by the leveling kit, so removing it seems to have helped so far.

Also, I drive fairly conservatively and my commute is more of a slightly hilly country highway with a few stop signs here and there.

So long story short, if your truck is lifted or leveled and still has the front lower spoiler, give yourself 5 minutes (which I think is pretty generous since it's only 2 bolts) and remove that lower spoiler to see if it helps your mpg. I'll try to keep an eye on mine and see if it's just a 1 tank fluke or not, but before removing that spoiler, I was consistent tank after tank in the low to mid 16 area, and this tank is at least 1 mpg higher.

 

Nice analogy, I think it's pretty early to get excited about. But I'll keep that in mind on the front lower spoiler. I'm curious about the result after couple tanks.

 

Manufacturers are required by the federalies to produce vehicles that have certain MPG averages. Everything they do is ti reach the federally mandated goals. As soon as you do anything to change from stock it may impact fuel economy. Even changing tires from P to LT can affect MPG.

All the things you mentioned have negative effect on mileage.

 

I agree with both of you. Yes it is too early to be excited, but every tank given the changes has been consistent for me, and this tank was abnormally high after the level.
Also, yes, every change negatively effects mpg. And each one has in my experience, but I'm not saying my mpg is better now than it was when completely stock or anything. It's just my experience SO FAR that it's better after the level. My mpg was better before the level either way, so that's not what I'm trying to say. I'll try to keep updated after a couple tanks.

 

Not trying to give you a hard time, but it seems like a fluke. I can't see how removing the air damn would help. It may not be optimized for a leveling kit, however would still help to move the air around the truck better than none at all.

 

Na, it's cool. I just wanted to throw it out there for everyone else in case someone else with a similar setup wanted to take a couple minutes and give it a try as well. It's put mine up around 1 to 1.5 mpg as of right now and where it used to be. The only thing that changed from the last tank to the current with better mpg is the removal of the spoiler. Also, I believe with how conservative my driving is, a change of driving habits wouldn't be a very realistic excuse.

Anyways, if anyone else is lifted or leveled and still has the spoiler on, take a couple minutes and remove it. Worst case scenario, you just lost a few minutes of your day. I'm going to leave mine off for a while and I'll try to make sure to report the dash mpg per tank and we will see what happens.

 

I took mine off after the level and bigger tires just because it was ugly. Just my .02

 

That's why I took it off both times really. The better mpg is just a bonus this time. Hell, even if it is just a fluke and the mpg ends up being about the same or even slightly worse, I'd consider it an improvement just for the better looks.

 

Well, just filled up for the second time after removing the spoiler. First tank was 17.2, second at 17.5. That's 2 in a row of being ~1mpg or so higher than my previous average.

Just thought I'd throw it out there.

 

Thanks for the updates...my truck is still stock height and getting an overall ~17.8 mpg which is pretty good at 7200 ft elevation. Yours is doing well with the leveling kit. Do you have the stock tire size?

A front spoiler would be used more for high speed stability than fuel economy. By reducing the amount of air going underneath a vehicle a small but helpful down force is created and a vehicle will track a straighter line. The spoiler could also help the overall air flow around the truck and make it slightly more aerodynamic helping the fuel economy. So my guess is that once the truck was lifted the angle of the spoiler changed and now was just catching air rather than redirecting it.

 

That's pretty much what I was thinking after I noticed the improvement. But yea, when it was stock, taking it off I lost around 1.5-2mpg.

Stock tires still on the truck, size is 275/55r20. For now at least, lol. After they wear out I'm getting 35s and I can say goodbye to the mpg