While driving home after a wonderful 4th of July weekend, I was dragging my 2 wheel utility trailer with my Kawasaki Mule on it.
My poor 2008 Mark LT with the 5.4 Triton 3V V8 could barely make it up the hills at 65mph. Sometimes it was in second gear going downhill just to get up to the 70 where I had the Cruise set. (The speed limit on this stretch of road is 80.)

The embarrasing part.....I was getting passed by Rams and Chevys pulling BOATS! Heck even a Subaru with a Harley on the trailer went past me.

Years ago, I would have said "plugs and wires."
Well, this machine has no plug wires so that can't be it. And, I have heard the horror stories of replacing the sparkplugs on these beasts.

So, time for some insight....is this a 105thousand mile machine? Or can the honor of a dressed up F150 be saved?
What are your thoughts?
If I choose to get the plugs replaced or replace them myself, what do I need to look out for or do?
I had a lot of time to think about this as the Chevys whizzed past me I have had Fords all my life, but this is embarassing.
Thanks for your help.

Details-
2008 Mark LT 5.4 Triton 3V
105K Miles
Burning 87 octane pump gas
Air filter is clean (new)
Pulling 15' utility trailer with Kawaski Mule aboard
Bed loaded with 20 gallons of water (4-5gallon cans), misc. tools and a couple coolers
Traveling Interstate 25-Speed limit 80

Let me know if you need to know more.
Thanks

 

105,xxx miles on OEM plugs, you are ready. Might not help power. Was it skipping or missing? You said "Years ago, I would have said "plugs and wires."". Why I asked. You do have plugs. Lot's of posts and YouTube videos detailing plug change.
How about the fuel filter?

Any codes? Stock gearing & tire sizes?

 

You have to check your build date ,you could have 07 heads . I any case yes you do have wires and plugs . The boots and springs are the wires, change them all . Clean all cop contacts . If old heads/plugs have lisle extractor kit first . Plugs only good for 60k . You must do a proper hosp clean plug job .

 

Thank you both.
Yes, stock gearing, stock tire size-new Big Os on all four corners.
I think you confirmed my suspicion. Yes-time for new plugs.
At this point it is more a fear of the unknown regarding changing the plugs and cops.....horror stories, busted plugs, access problems, etc.
It is probably a matter of "the monster in the closet is bigger than the monster in front of you."
I will re watch the videos and tackle it this week.

Something must be done to reclaim this Ford's dignity.

 

Dare I ask if you might've had the parking brake engaged the whole time?

 

I wish it was that simple. That is exactly what it felt like. So yes I did check the brake. Thanks for asking though.

 

To all who have read/lurked/commented-plug replacement set for four days from now. I will post after the project is complete.
Thanks for your help.

 

I'll be curious to know what the gaps are when you remove the old plugs.

 

Do you have the new heads ?Which are different plugs and not a problem removing . Another thing to watch for is sticking calipers and severe heating/damaging wheel bearings etc . .Pistons are composite absorb moisture and start sticking .Fix is rebuilt calipers.

 

Dont forget new coil boots.

 

I will measure and post after the project is complete.

 

Good point. Will do.

 

Watch this: Start around 12:50.
Your intake may be clogged.

 

I ran up the Ike with my 2005 F150 5.4 towing a loaded 10' enclosed trailer. By the time I got to the top I was down to 60 mph but hey, you're at 11,000 feet! Oh, and it had 188,000 miles on it then, now I'm at 198,500. Anyway, my point is, something is definitely wrong with your truck!

 

What about a possible exhaust restriction on the OP's truck? The usual suspect would be a catalytic converter. If the plugs don't help that much that would be the next place to look.