Hey @KiskaWoolf0011, welcome to the forums!
It could be an issue with the order you are casting the nodes from, and for some reason, the cast is only getting called once again around the 40km/h range. I’ve found a few other threads that talk about this,
and
https://www.reddit.com/r/unrealengine/comments/zlrpbe/how_to_access_engine_rpm/
Could you share a screenshot of your implementation? I might be able to help more if I could see the blueprints.
Let me know if this helps!
-Zen