2004 f150 supercrew 4x4 5.4 motor 252000 miles 33x12.5x20 tires 2.5 in leveling kit. So I picked up a 20 ft pontoon boat I couldnt get the truck over 70 in a hilly area but on flat road ran up to 75 no problem. The motor does have a slight tick but you can only hear it outside the truck or in a drive throught with the radio off. Truck has no codes snd starts and runs fine.

 

70 to 75 mph towing a lump like a pontoon boat is way too fast for good sense

 

Im glad you can throw in your useless opinion heres is a good idea if you cant offer helpful info dont offer any.

 

How fast do you want to go? What is the speed limit?

 

Im some places 75. I only asked cause pedal was to the floor and it seemed to struggle to maintain 70 on the hilly area.

 

How fast do you expect a 5.4 to go with a pontoon boat behind it? Especially one with 250k miles?

I concur above about the speed; brakes on these suck, especially with a trailer behind it. Keep it below 65.

 

Honestly the boat isnt even half the towing capacity of the truck. I was only asking because it struggled to maintain 70 in a hilly area. Apparently actual help is not possible. I was just wanting to know if there was something I could check or replace.

 

If you want a good idea of why your 250k mile 5.4 can't maintain 70 mph up hills, start with a compression test, spark plugs and injectors. But since it is "running fine," the reason is that it has a well-worn 250k miles. These trucks won't hold 70 up a hill with 3-4k behind them without a lot of throttle, I don't really know what more you're looking for. These trucks were the slowest of the full-size when they were new, 15 years and 250k miles aren't going to make them better. A pontoon has a lot of wind resistance, which increases exponentially with velocity; you're driving with a sail behind you. Like mentioned, stick with sane speeds and you'll be fine, you're trying to do something the truck was never designed to do. Even my unloaded 700 lb landscape trailer with a mesh loading ramp adds noticeable resistance.

 

Now that I can go with I only wondered because my 1648 bass tracker 3 on trailer that totaled about 1200 pounds it didnt even seem to have any effect.

 

Sorry. My helpful info is slow down. You are not doing your truck or trailer any good. As previously stated, wind resistance is your biggest problem.