Need help from other 2015-16 F-150 5.0 Owners
 

Hi everyone,

I need help from other 2015-16 F-150 5.0 Owners to see if this is normal behavior or did I get lemon. I am a Network Engineer by trade and know from experience computers are not infallible and need to be checked once in a while to make sure they are correct.

I have a 2013 Mustang 302 Boss, when I check the gas mileage it is dead on with the display with the max of .2 tenth of a gallon off. Last fill up it said I used 9.2 and in reality it used 9.4 totally acceptable margin

With my 2016 F-150 5.0 I am getting 2 to 2.5 Gallons off.. which to me is a huge red flag that something is wrong if the Computer say it you should have gotten 17.1 Mpg and it is only getting 14.5, I took it back to the 5 Star Ford dealership which was a huge waist of time. They plugged a computer in to the computer and it said that it is fine... really? I asked did you ever top off the tank and do the manual math...? No we didn't that is not the industry standard test for mpg. What the hell that is the standard for the last 100 years since cars were invented.

If other 5.0 Truck owners can test their trucks to compare what it reports verse reality and let me know if theirs are close to what is reporting or wildly off like mine it would be a big help. I have a feeling I got a lemon and will need to get rid of it.

Thanks

well, aside from leaving out a whole lot of information, it seems like you've already made up your mind.

I bet the truck idles a lot more than your boss.

Their are so many variables that could effect this. Weight in bed, headwinds, type of fuel, tire pressure cold weather, idle time, traffic, using 4wd, etc, etc.

Did you actually ask them what their standard test is? Because the last Ford document I've read on the topic (which is admittedly OLD by any standard) says that's exactly how to find MPG. Click this (on a computer with a fullsize monitor - not a phone) & read it and its caption (below the image):

https://www.supermotors.net/getfile/...pgtechtips.jpg
(phone app link)No, nothing affects the calculation of miles per gallon (miles/gallons), which is what he's asking about. You're talking about what affects FUEL ECONOMY - a different subject. None of the factors you listed are a part of the very simple mathematical formula MPG = Δmiles/Δgallons . The best computer available to any dealership service department can't detect, calculate, monitor, or correct the actual miles a vehicle has been driven (beyond what the operator can see on the odometer), or how much fuel has been put into it.That's a valid point - the amount of fuel used during idling will affect the calculated MPG, but the instrument cluster might be programmed to ignore that consumption, and only display the MPG during driving.

Tire Pressure normal set to what is recommend on the vehicle documentation. Not towing, just normal city / highway driving, it has been the same since the first fill up at 300 miles on the tac now at 8200 miles. Does it in the summer and in the winter that is why I said 2 to 2.5 Gallons off, it is a worse in the winter like one would expect. When the dealer was looking at my truck I had a F-150 Eco V6 loaner when I did the manual math the dash display said 17.7 mpg and when I crunched the math the truck got 17.2, that is what I expect.. it was off by 2 tenths.. not Gallons off. 2016 2x XLT Sport model. I have done long highway trips and it is always 2 off, if it says I got 20 but really I got 18, 17 then I got 15 to 14.5 etc. It is not that I expect an economy car but I always check gas mileage on my vehicles since if there is something not working right it will show up first in your gas mileage before you will feel a power drop. I do not believe the issue is in the motor sounds very smooth, but something is dragging it down and not running efficient.

Also always use top tier gas, just Shell and Exon, I was just curious if other 5.0 F-150 owner have the same results, I talked to another F-250 owner here at my work and he said that his is dead on or just 1 or 2 tenths off but his is not a 5.0 motor. If everyone reports " My truck is off by 2 gallons too " Then I may think it is normal but if most report mine is only .2 tenths off like I expect from my experience with Ford motors then I know there is an issue unique to this truck(First Ford was 1990 Mustang GT 5.0 and have owned 26 years of Ford V8s)

It’s called a lie-o-meter for a reason. Mine averages around .6-.9 too high vs. hand calculation. The most I’ve been off is 1.2. It’s well documented on the forum. Most report too high regardless of the engine.

Steve83,

Yes thank you someone gets it. The very simple mathematical formula for MPG has people very very confused, like I am filling up the tank wrong :-O. A new Truck should get more than 14.5 with combined city and highways driving, it should get the 17 that it is reporting. The same as my 99 Durango that I traded in when I got this truck you would think with the newer tech it would get mpg as reported. My truck does not idle more than my Boss, the worst idea I have seen yet LOL how does that happen when I drive the same route to work? The lie-o-meter is very close to being dead on in many other Fords I have driven and tested, it is just 2+ Gallons is very excessive drop from what is being reported. It makes me think there is something dragging down the truck that it not related to the motor and the computer senors, like bad wheel bearing ( I am not hearing any noise from them just using a example of an mechanical part that the computer and motor would have no idea about but could affect performance.)

All I asked is if other 5.0 owners when they fill up their truck would check and see if there is as wildly off as mine, if no one reports a 2 gallon drop then I know something else is going on. It is just frustrating on a new vehicle that is under warranty I would need to troubleshoot work on since Ford service has been totally incompetent, it would not be an easy one to troubleshoot and they got the vehicle sale already, want the easy money of an oil change but bring in a hard issue that is not a check engine light, totally dropped the ball. The first step of 101 troubleshooting is duplicate the issue the customer is reporting, I know because I troubleshoot networks for a living.

on my 14 and my brother's 15, 90+% hwy mileage the mpg and gallons used is usually very close to hand calculations. City mileage is usually a couple mpg and gallons off. Its normal.

When I have just filled up so the average is for only 1-2 miles then get stuck at a red light, the mileage drops while sitting there, right before my eyes. It does appear to be affected by idling. I happened to need filling up so I checked, and my figure on the dash was 15.7, actual hand calculation 15.2 - but mine is a 2017, so could be different.