My sim keeps running away

@lexiegoodall , thanks for the additional information.  It helps to see if the problem just exists in one save file, which can happen if just that save file gets corrupted. 

This is most likely to be a Mods/CC conflict.  This can happen any time the game gets updated/patched and the makers of the Mods and CC items don't also update their creations accordingly.  EA cannot work around the thousands and thousands of CC items and Mods, so it is up to the CC/Mods creators to keep up with the game as it changes. 

I know it can be daunting and tedious to keep up with a bunch of CC and Mods, but in order for your game to run the best that it can, you need to do so.  If you don't like maintenance, then it is best to use only a few Mods/CC or not use them at all. This is why I don't use Mods/CC (I hate maintenance! 😅).  But if you want to continue using a buch of Mods/CC, then you will need to do maintenance on them, and once you find the broken ones, either replace them with the updated versions, or if the creator doesn't update their creations, then you will need to delete those items. 

Here is a good procedure for finding which Mod or CC item is outdated:

1) Move the Mods Folder to your desktop

2) Delete the localthumbcache.package file in the game folder. This is important because it can contain bits of corrupted data even after you remove your CC/Mods! 🤨 This is found in Documents > Electronic Arts > The Sims 4.

3) Fix you game in Origin by logging in and go to Library, then right-click on The Sims 4 and choose the "Repair Game" option from the list.  Wait until Origin finishes repairing all your packs and not just the base game.

4) Now, when you turn on your game again, it will create a new mods folder that will be empty.  Check to see if your game is now working without mods/CC.

5) Now you can try adding back items from your Mods folder one at a time checking your game each time to see which item is causing your game to not work properly.  If you have a lot of items, you can try the 50/50 Method, working in batches to see which CC item or Mod is the culprit. (You could have multiple items causing problems.)

The Mods/CC creators will usually update the CC items and Mods after these updates, so when you find out which one is the culprit, you can get the updated version from whoever made that item of CC in the first place.  You should try these steps anytime you have problems in your game to rule out CC/Mods problems.  It is the responsibility of the Mods/CC creators to update their items anytime EA releases a patch/update, and it is the responsibility of the people who use Mods/CC to make sure they are using the most recent version.

When you find the updated version of your CC items, you can put them back into your game. 🙂

Many people aren't aware of step #2, so be sure not to forget it!  You will probably end up using the 50/50 Method to find which CC items and Mods are the ones causing the problem, since you stated that you use a bunch of them! 😉

I know it is a pain, but it needs to be done if you don't just want to stop using Mods/CC altogether! 😓  This is why it might be easier for you to just choose the Mods and CC items you like the most (that have been updated) and just use those, so you can cut down on the time it takes to do regular maintenance! 
😉
Please update us on the results of this! 😇