The gauge should not stay on after the engine is off. However, your gauge needle may stay where it is when the engine stops. It might not return to zero when off.
No the needle will stay in the same spot and will always show the amount of gas you have in the tank, engine off or on doesnt matter I had an 04 rio and it always stayed in the same spot
Search Kia Rio Questions
Kia Rio Experts
Related Models For Sale
Used Cars For Sale