Have your wheels rebalanced. Perhaps one shed a weight.

 

Nope normal tires.nothing special. I'm thinking of just dropping it off at my mechanics and have him check it out. Its raining here so I don't feel like rolling around on the ground haha. I'll let you guys know what he says. Thanks for the suggestions.

 

Got my truck back today. Had a bad wheel bearing. Hope that solves it. Thanks for the ideas everyone.

 

So my truck is back at it. This time without the boat trailer so it's definitely the truck. My mechanic has balanced aligned and rotated my tires and changed my front passenger wheel bearing. That didn't fix it. Yesterday the feeling came back. It started around 55mph and any speed above. As soon as you get off the highway it stops. Best I can describe it is it's like your running on the rumble strips on the side of the road. Just without the noise.

Any ideas?

 

I had a belt seperate on 2 tires, felt weird for a while but could not see any problem
1st one I had Sullivan tire check out, belt gone...it had been leaking air due to a nail
2nd one I had the belt give way & the tire went flat -as I was pulling over to check it
Happened about 2 years apart w/orig tires

 

Perhaps an intermittent dragging front brake caliper?

 

It sounds to me like either your shocks are 100% dead, or you're experiencing axle wrap. It's basically where your axle is twisting and flexing your springs awkwardly. A rear track bar would probably fix it. Towing a lot can do it, so its possible that replacing leaf springs could help. I've never really heard of this on an f150 but I'd still check it out.

Good Luck!

EDIT: Your axle could also be bent. Your wheels could be bent as well. A large impact while towing a boat could cause this.

 

If the axle was bent,wouldn't I feel the shaking all the time? I drove to Rhode island last week, an hour and 30min ride both ways and never had an issue which made me think that the wheel bearing that was replaced was my problem. Then the other night I went maybe 10miles and the shaking came. I feel like it could be a ton of different things. From what I've read in other forums, I'm not the only one with the problem and nobody has found a cure.

 

I still say its the U-joints. Mine does the exact same thing

 

That makes me suspect plugs and ignition coils.