Likely you just need a new crankshaft position sensor. Buy a Kia part.This car is driving me crazy its at the mechanics now and is not throwing any codes. Yeah me .. It has happened 3 times now. When you turn the car off it works again. And when it has no RPMs it still has power and can be driven. But NO i don't drive it..until my RPMs come back
You can also search the forum for “crankshaft position sensor” and find others having similar issues and solutions.
It does set a code but it doesn’t store it for some reason. The next time it happens, don’t key off the car. Plug in your scanner and it should show a code. Once you take the key out then turn it back on the code will be gone.