Disgusted with fuel mileage
10-06-2014, 02:33 PM
#11
I have the UltraGauge that was mentioned above, and one of the things I like about it is that it gives you more than just instantaneous. I can do average by trip (reset whenever the truck is stopped for more than a few minutes), or since I last reset the "master" MPG calc.
It also lets me monitor other OBDII values - when I was getting a CEL for long term lean codes, I could watch those numbers and try different things and see if they were actually going down or not. When I put a winter grill block on, I could monitor the engine temps and see if it was overheating the engine at all.
It also lets me monitor other OBDII values - when I was getting a CEL for long term lean codes, I could watch those numbers and try different things and see if they were actually going down or not. When I put a winter grill block on, I could monitor the engine temps and see if it was overheating the engine at all.
10-07-2014, 10:13 AM
#13
I am assuming those are LT tires because I cant seem to find any P-metric tires in that size (I have looked because that's the size I want). those are HEAVY tires to begin with and depending on what size is stock on your particular truck, they could be quite a bit taller than stock as well. is your speedo calibrated to the bigger tires?
if it's not, then I hate to say but your mileage might be EVEN WORSE than you think it already is.
your best bet is to go back to a stock size p-metric tire.
10-07-2014, 10:35 AM
#14
Stock tires on the Lariat seem to be 265/60-18, so that's almost 10% bigger than stock. That should mean that your fuel economy is slightly *better* than reported by the truck, though - when it thinks you used a gallon to go 12 miles, you actually went 13 miles.
10-09-2014, 10:17 AM
#15
Sluggo33
Fuel mileage dropped after getting new tires.
I was running the factory Michelin P265R60-18 and switched to BF GoodrichLong Trail TA same size and my mileage dropped by almost 2 MPG. Normally get18.9-19.2 Hwy/City with old tires. Now averaging 17.4-17.9. Same tire size justthe Long Trails have a little more aggressive tread pattern. Any ideas?
10-09-2014, 07:39 PM
#16
I was running the factory Michelin P265R60-18 and switched to BF GoodrichLong Trail TA same size and my mileage dropped by almost 2 MPG. Normally get18.9-19.2 Hwy/City with old tires. Now averaging 17.4-17.9. Same tire size justthe Long Trails have a little more aggressive tread pattern. Any ideas?
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sluggo33 (10-21-2014)
10-09-2014, 07:40 PM
#17
Senior Member
I was running the factory Michelin P265R60-18 and switched to BF GoodrichLong Trail TA same size and my mileage dropped by almost 2 MPG. Normally get18.9-19.2 Hwy/City with old tires. Now averaging 17.4-17.9. Same tire size justthe Long Trails have a little more aggressive tread pattern. Any ideas?
All seasons generally give better mileage than all-terrains because of a less aggressive tread pattern.
Some of the tires they put on high mpg cars have especially designed rubber compounds to improve mileage. They may not be as grippy as regular tires though.
There are trade-offs, for sure.
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sluggo33 (10-21-2014)
10-11-2014, 02:12 AM
#18
Senior Member
You said the K&N was already on the truck when u bought it. The PO
May have done other mods you may not be aware of. Have u had the Computer
Reflashed there may be a tune on there hurting you or he may have changed the throttle
Body or fuel injector size who knows. It is always concerning to me when buying used to see performance add owns because you just don't know to what lengths they may go. I image the 2 inch level on the front hurts you some too over the factory rake. But it does look better level. I believe I would start with a Reflash to rule that out. Just one more
Opinion for you
May have done other mods you may not be aware of. Have u had the Computer
Reflashed there may be a tune on there hurting you or he may have changed the throttle
Body or fuel injector size who knows. It is always concerning to me when buying used to see performance add owns because you just don't know to what lengths they may go. I image the 2 inch level on the front hurts you some too over the factory rake. But it does look better level. I believe I would start with a Reflash to rule that out. Just one more
Opinion for you
10-11-2014, 12:57 PM
#19
Senior Member
You said that it had the K&N air filters in it when you bought it used. Clean or replace the MAF (mass air flow) sensor. With my own experience with K&N intakes I had crappy gas milage and it idled sometimes goofy, you could only tell be they rpms on the tech and it did not through off any codes. It was in my Nissan Maxima and it started around 80k in year 5 and I was the original owner.
I NEVER over sprayed my air filter with the K&N oil, but over time it coats the MAF sensor with a fine coating of air filter oil and causes problems. In my trucks I never had any problems. Get some throttle body cleaner and with the engine off spray a little bit it into the intake just past the filter. Do that a few times and let it stand for a while (hour or so) reinstall everything and give it a shot.
If you google "over oiling the air flitter on K&Ns, I remember a whole bunch of stuff popped up. For my car, it increased gas mileage by 2 or 3 MPGS and took care of the idling thing.
I NEVER over sprayed my air filter with the K&N oil, but over time it coats the MAF sensor with a fine coating of air filter oil and causes problems. In my trucks I never had any problems. Get some throttle body cleaner and with the engine off spray a little bit it into the intake just past the filter. Do that a few times and let it stand for a while (hour or so) reinstall everything and give it a shot.
If you google "over oiling the air flitter on K&Ns, I remember a whole bunch of stuff popped up. For my car, it increased gas mileage by 2 or 3 MPGS and took care of the idling thing.
10-11-2014, 01:44 PM
#20
Senior Member
Changing your plugs ..... will help a little
Hey guys, I've had my truck for two years now and love pretty much everything about it except the fuel mileage. It has got to be the most inefficient pickup on the road.
I have a 2004 (not heritage) F150 4 door Lariat
K&N intake
Aftermarket exhaust
Two inch leveling spacers in the front
.355 gears
Steel cowl hood
Soft bed cover
90,0000 miles on stock plugs
I can't think of anything else that would be useful information as far as fuel mileage would go.
When driving without hauling anything I get around 11.5 MPG and I would say that's 70 percent HWY and 30 percent city,
When Hauling my 8X12 enclosed trailer v nose with a couple of motorcycles in there I get 8MPG. The terrain doesn't seem to make a difference either way with towing. I also do keep OD off to keep from excessive shifting.
I love the truck, but I tow my motorcycles to the track often and the fuel cost is getting kind of crazy. I know the plugs are due, which I'll get to soon, but I was wondering about the K&N cold air intake. I've heard of the oil from the filter getting on the mass air flow sensor fooling the motor into running rich. I bought the truck with it on there so I can nothing to compare it to prior to it being installed.
So is this the norm of what others are getting around here, or do I have something out of the normal going on? Any input would be appreciated.
I have a 2004 (not heritage) F150 4 door Lariat
K&N intake
Aftermarket exhaust
Two inch leveling spacers in the front
.355 gears
Steel cowl hood
Soft bed cover
90,0000 miles on stock plugs
I can't think of anything else that would be useful information as far as fuel mileage would go.
When driving without hauling anything I get around 11.5 MPG and I would say that's 70 percent HWY and 30 percent city,
When Hauling my 8X12 enclosed trailer v nose with a couple of motorcycles in there I get 8MPG. The terrain doesn't seem to make a difference either way with towing. I also do keep OD off to keep from excessive shifting.
I love the truck, but I tow my motorcycles to the track often and the fuel cost is getting kind of crazy. I know the plugs are due, which I'll get to soon, but I was wondering about the K&N cold air intake. I've heard of the oil from the filter getting on the mass air flow sensor fooling the motor into running rich. I bought the truck with it on there so I can nothing to compare it to prior to it being installed.
So is this the norm of what others are getting around here, or do I have something out of the normal going on? Any input would be appreciated.
I had an 02 screw fx4 5.4 with a 6.5" fab tech lift and 35's ... , 3:55 , K&N , throttle body spacer and aftermarket exhaust same as you have , The fuel mileage was so Bad I never even bothered to find out what it was ...Im sure it was less than 8 mpg when not towing and probably around 4-5 mpg towing my boat ..... My newer 2013 screw 4x4 gets around 14.5-15.5 towing the boat .. its about the only thing I like better than the 02 , because that 02 was one great truck .. very few problems with it to speak of and it was used and abused but still taken care of ... damn dealer made 12k when they sold it ..... gave me 4,500 .... yep I got screwed on that deal
But it would a took me a few months to sell it out right ..didn't want to wait so its my own fault .... Anyway .... That 5.4 is a great motor but it is surely not good on gas .... If you want fuel mileage when towing you might think about the 5.0 or an eccoboost .... the mileage is about the same when towing ....the 5.0 sounds better and no matter what exhaust you put on an eccoboost ... it will always sound like a v6 
Last edited by GotHonks?; 10-11-2014 at 01:53 PM. Reason: forgot to mention ...