The infamous P0440/P0442 scan codes..... also known as the Gas Cap codes.
These are the most commonly reported codes for the Sporty for the 1998 to 2001 model years.
More times than not, a bad or leaky seal on the GAS CAP is all this is. The gas cap has a rubber seal that contacts the filler nozzle area. That is always the usual suspect. Look for cuts or nicks in that seal. Replace if it looks bad.
There is a pressure building and relief valve built into the Gas Cap. It allow the tank to build pressure to 3psi and relieve pressure if it has a vacuum of greater than 2 inches of mercury.
It is possible that this pressure regulator if you will, to fail and the cap will need replacing.
If you find our think your Gas Cap is ok, then you have many other areas to look at. The code is saying that the Gas Tank is not building pressure to the specified levels with in 2 driving cycles, so you are looking for a leak somewhere in the Evap and or Gas Tank system.
A helpful site is below, put in your specific data about your Kia and choose "Emissions Control System" and "Troubleshooting" to find the related DTC code information.
Global Service Way