Odd one to me (and its on the rig ride out of town so options are limited on diagnostic and fixing).

2021 F150 XLT 4x4. Get a vibation at highway speeds with throttle down. If i let up on accelerator is eases some. Only vibrates at 65+. Below 60 is nothing. But it also doesn't change much with speed/RPM (90-100 is the same as 70-80). Feels pretty even Left to Right & definitively in the front end.

Wouldn't think driveline as its not constant.

Tire Balance issue? Loose lug nut? both upper or lower ball joints?

Its -3F outside so trying to not spend a ton of time looking at things if I didn't know where to start.

Where to start?

Could be tires, worn suspension components, driveline, or something else. Have the tires balanced, check for loose lug nuts and any looseness in the steering and suspension. Does it behave the same when in 4wd?

its got new tires ~ 2000 miles ago. Vredestin's Pinza AT's. 275/65r18 put on by the dealership.

Wouldn't think its tires but maybe they didn't balance right. I'm not familiar with the brand.

Did you have the driveshaft insulation recall done?

I checked VIN and don't see it being needed.
Purchased from Ford Dealership in September so figured it would have been done when it went through the pre-sale check.

Is it lifted or leveled?

Have you gone through deep mud recently? I've had mud get caked on the inside of the rims and only noticed it at 65+ before.

Bone stock, wheels are clean, no lift or level.

Wondering if wheels didn't throw a weight or something.

FunnyFarm14 said:

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Bone stock, wheels are clean, no lift or level.

Wondering if wheels didn't throw a weight or something.

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I'd start with balance and rotation first.