Sephia randomly sputters

My 2001 Sephia will randomly sputter while shifting gears. When I give it gas is when it sputters. It doesn't do it all the time. I thought that it might me either a fouled plug or wires. Maybe it could be the fuel pump. If I change the plugs does anyone have any ideas on how I go about doing this. I have changed plugs on other cars but the Kia looks alot different then most. So if someone could give a quick instruction on how to do this that would be great.