How do I replace the fuel pump in a 2005 Kia Optima

Modern-day fuel pumps are very reliable. Even though people focus on and replace many fuel pumps, the problem usually ends up being something else; e.g. fuse, relay, ECM, or ignition switch. In fact, I have yet to see one fail.

When you turn the ignition switch to ON, do you hear the fuel pump in the gas tank run for two seconds? If not, test all underhood and underdash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post252145

Likewise, ensure that the fuel pump relay works.