Originally Posted by veganbikes

Curious what you replaced the rear wheel with? It could be the new wheel is also not true or you replaced some of the worn out parts but there are still worn out parts. The frame could be damaged or something else entirely. A Huffy unfortunately is not worth putting much of anything towards money wise. In the end you can just buy a new one that will eventually have the same issues and likely have some issues from new but at least will be new.

You could also save up and buy a bike that will work for mountain biking or if not mountain biking for whatever riding you are doing. If you go to a bike shop they can help you get a new bike which will work a lot better and have good support behind it. You can also take the current bike to the shop and they can take a look at it and probably suggest buying a new bike a worn out Huffy is not really designed to be fixed and repaired without likely costing more than the bike is worth new.