2002 With rough idle

My 2002 Blazer was idling rough and giving a misfire code. After replacing plugs(Gaped), cap, rotor, filters(air/fuel), and wires I've still have a rough idle. The code still comes back when I let it idle in gear(automatic) at a stand still, but disappears a few min later. Its only got 38K miles and constantly idles at < 700 RPM. Any suggestions?

Check your Trottle Position Sensor's voltage