Engine stalls even with full tank of gas, no codes are coming up

If it only does it while the tank is full then look at the tank venting system, it could be stuck open causing the engine to run rick and flood out. However if it does it at any time then start with the crankshaft sensor and cam sensor, these will not set any code unless shorted, an intermittent will not be read by the Kia computer. Find a shop that has some experience with "seat of the pants" diagnostics, in other words a person that's been around the block a few times. A lot of shops will say if the computer has no codes then that is where they stop. They won't go further.