Gas Mileage for F150 5.4

maybe things have changed but it used to be true for almost any gas TV and any combination that the towing mileage would be very close to half of the non towing mileage… with driving style playing a major role in the + or – from that half, and that can be significant in cost over time…

even hills unless only going up- hill didn’t seem make much difference for me something I haven’t experienced yet… it seemed going up hills used more only to be averaged out by the going down the other side, resulting in flat towing often being as bad as or close to it overall…

I say seems because I never kept or calculated mileage over a short distance or a single tank of gas, so all of my averages included all types of road and conditions with similar results every trip to different destinations…


Fords spark plug issues per Wikipedia for those that might not know…

2-valve 4.6 L, 5.4 L, and 6.8 L engines found in many 1997–2008 Ford, Lincoln, and Mercury vehicles have an issue with stripped or missing spark plug threads in the cylinder heads. Ford acknowledges this issue in TSB 07-21-2 as well as earlier TSBs. Ford's TSB does not state that this issue is caused by owner neglect. Ford's only authorized repair procedure for out-of-warranty vehicles is to use the LOCK-N-STITCH aluminum insert and tool kit. For vehicles under the New Vehicle Limited Warranty, Ford will only cover the replacement of the entire cylinder head; however, the Ford recommended spark plug service interval extends beyond the duration of the New Vehicle Limited Warranty.

3-valve 5.4 L and 6.8 L engines built before 10/9/07 and 3-valve 4.6 Ls built before 11/30/07 found in many 2004–2008 Ford, Lincoln, and Mercury vehicles have an issue with difficult to remove spark plugs which can cause part of the spark plug to become seized in the cylinder head. The source of the problem is a unique plug design that is made with a 2-piece shell, which often separates, leaving the lower portion of the spark plug stuck deep in the engine. Ford acknowledges this issue in TSB 08-7-6 as well as earlier TSBs. Ford's TSB does not state that this issue is caused by owner neglect. The TSB provides a special procedure for spark plug removal on these engines. For situations where the spark plug has broken in the head, Ford distributes multiple special tools for removing the seized portion of the plug. The multiple procedures required for the different cases/situations of plugs seized in these engines are explained in the TSB. This repair is covered for vehicles under warranty; however, the Ford recommended spark plug service interval extends beyond the duration of the New Vehicle Limited Warranty.

Federal-Mogul, parent company of Champion Spark Plug, and Brisk Silver Racing have introduced a 1-piece machined shell 3-valve spark plugs that addresses the OEM 2-piece spark plug's separation issues.

Just did mine a week ago. Broke three out of 8. I'm of the opinion that if they're going to break, they're going to break, doesn't matter who does it or how.

Mileage towing 8000K: 7 out west, 9 around PA. 4.10 rear and 4 speed. Good luck with anything higher.

You win some, you lose some. At 70k I had the problem.

Had my plugs changed at 70K, any decent mechanic can pull them without a problem much less damage. New ones get a coat of never sieze, nothing special there. Too many folks left them in for 100K and then tried to just muscle them out.
:C

Ford screwed up when they put in the spark plugs for the 5.4. The plugs fuse themselves to the engine block and need to be forced out which generally breaks them. Then they have to extracted which can cost up to an extra $85/broken plug. I changed mine at 70k and they were fused in there. All but one broke. I was lucky to find a dealer who wouldn't charge me for each extraction. Even then it cost me $465. When they put new ones in they coat the threads with a special compound that prevents that condition. They suggest changing the plugs at 100k. However, in face of what happens I recommend biting the bullet and getting them changed ASAP. You may be in time to get some out without breakage. Too bad Ford doesn't cover the cost of their blunder.

Thanks for all of the feedback. This is a great place to get info. We're taking the TT on a test this weekend. Round trip should be around 140 miles. I'll check the MPG.

I did a little research on the spark plug issue that was mentioned. I'm floored SP's would cause that much of an issue. My truck is right around 60K and running fine. I'm tempted to leave them in a little longer until my bank account recovers from buying the trailer.

Good travels!

dadmomh wrote:
Midway through our trip from West TN to Durango,CO. Uphill for a zillion miles and the only time we checked was 8.9....didn't want to know any more. Now we're headed downhill and life is good...haven't checked but we know we're about a tank less than going.

We're pulling a Rockwood 2604 - 6629# - with an '03 5.4. We usually are just about 10 mpg. With our ROO 23SS, didn't make any difference, still about 10mpg.

Speed makes a huge difference, so put that foot on a diet - not only for better mileage but for everyone's safety. Seems like most here tow between about 57 - 65 tops.

On the uphill part of the trip, passed a TT on its side against the guardrail. Truck with bicycles was down in a gully with an ambulance very busy.....can only hope everyone was ok in the long run. Makes most feet lose a few seeing that. Safety is the important part....forget getting there a few minutes earlier.

x2 on speed. I run @ 60mph on the interstate. Everyone deals with it easily including the tractor-trailers. If I move it up to 64-65 I lose up to 1-2 mpgs. Costly at today's fuel prices.

Midway through our trip from West TN to Durango,CO. Uphill for a zillion miles and the only time we checked was 8.9....didn't want to know any more. Now we're headed downhill and life is good...haven't checked but we know we're about a tank less than going.

We're pulling a Rockwood 2604 - 6629# - with an '03 5.4. We usually are just about 10 mpg. With our ROO 23SS, didn't make any difference, still about 10mpg.

Speed makes a huge difference, so put that foot on a diet - not only for better mileage but for everyone's safety. Seems like most here tow between about 57 - 65 tops.

On the uphill part of the trip, passed a TT on its side against the guardrail. Truck with bicycles was down in a gully with an ambulance very busy.....can only hope everyone was ok in the long run. Makes most feet lose a few seeing that. Safety is the important part....forget getting there a few minutes earlier.

APT wrote:
8-10mpg for every gas engine for every TT. Pulling two sheets of plywood through the air is the equalizer.

I do think that the newer trucks get better gas mileage pulling a TT. I had a 1970 van that would get 11mpg unloaded on the flats at 60mph.

My 2014 1/2 ton pulling a TT will get 11.5mpg even in the foothills, and will hit 12mpg on the flats at 60mph (without wind). Serious mountain driving or headwinds will drop it to 10. I can get 9mpg any day of the week by driving 60 with a 20mph headwind (or driving 80, but that's inadvisable, and I don't do it).

When you're talking fuel economy near single digits, every mpg you gain is a serious improvement, percentagewise, in economy, and therefore at the pump.

For what it's worth, this is pulling a 6,500lb trailer; pulling up hills with a heavier trailer will decrease those mileage figures somewhat (on the flats, wind resistance is solely what "drives" the fuel consumption). Obviously every mph over 60 or 65 will have an increasingly large impact on gas mileage.

On a recent 2000 mile trip, I figure I saved almost $200 in gas by getting 11.5mpg instead of the 9.5 I would have gotten with my older tow vehicle. Over 50,000 miles of towing, that's $5k saved in gas alone. And the new truck pulls and drives better in every conceivable way.

2010 F150 5.4 3.15 gears pulling Jayflight 24RKS.. 24 ft box 5200 lbs empty, not sure full weight...
I get 8 to 10, haven't done mountains with the trailer, only hills and flat lands.. get best mileage at 55-58..