Is this relevant?

 

I tried that & it didn't work. My rattle noise was coming from the bars banging around inside, not the top piece moving.
Ended up using two ~1" pieces of leftover tailgate seal (tapered rubber with an adhesive back). I stuck them on the bars in the right place, so they jam into the plastic sleeve that the bars slide into, but the step will still latch normally. No more rattle, at least until those rubber pieces wear out.
Thanks for the helpful replies!

 

One of the few things my '14 had, that I wish my '20 had. I've missed having that step on plenty of occasions.

 

My last 3 trucks had the step and it is an option I wouldn't want to be without.
None of mine rattled like the OP's, but I think I'd rather have a rattling step than no step.

 

Interesting, I didn't have it in my last truck and didn't feel it was that useful a feature for me. Now that I have it, I rarely use it. Partly because of old habit and partly because it's faster to just hop up. However, these knees aren't getting any younger lol.

 

Spray foam.

 

I installed this step on my 2018 F150 XLT (without factory step). It works great, is extremely tough, and can be used with tailgate open or closed.

AMP Research Retractable Bumper Step - Ford F150 2015 - 2019

You could install this, and take a couple sheets of Styrofoam packing material, and stuff them down into the factory step opening, rendering it immobile. That should stop the rattling.

 

Interesting, but expensive. I think I'd buy a low step-stool to keep in the bed.

 

You can relieve tension on the torsion bar, or disconnect it entirely.

 

your right I just never got back to it after all was finished. Looks pretty funny waiving to people at the dragstrip