I’m working on a game where your rig is a cat. I imported one from the toolbox, and it seems like it’s having issues balancing itself. Please help! 
As you can see, it wobbles when you change directions, and when you jump backwards, I’m holding S and i move in undetermined directions.
Did you make any changes to the toolbox model when you put it in your place? If you did go back through your changes and see which change caused the issue.
If that doesn’t work and the model is a few years old there may have been changes to physical Constraints that the script uses to move the model.
When was the model put into the toolbox? Are there any poor ratings, or any comments on the model saying it doesn’t work or it’s broken?
If you go through all of the steps above and none of them work it could be a scripting issue. Then you’d have to copy/paste the script here but change the post to Scripting Support instead of Building Support. This Building Support section is for help with placing Parts or the actual process of building, not really for topics like this.
a friend gave me the model, so i can’t really say much about the model itself. it’s overall a physics issue with the humanoid’s balancing.
Well the issue is clearly how physics is applied to it.
Last time I did something like this I had to just play around with different settings here and there to get it working. First off, try disabling collisions for all parts except torso/head (maybe just torso). Make sure every other part except the torso or humanoidrootpart, whichever applies in this case, is massless.
disabling collision for the legs will result in the character falling into the floor, so make sure to increase humanoid hipheight accordingly to make it the same height as the legs.
and again, just try playing around with it to get it to work.
Is it possible to ask the friend who gave it to you about how it works?
If not do as @Gucci_Dabs222 suggested in their post.