The 2004 GFS Marketplace 400 was the 23rd stock car race of the 2004 NASCAR Nextel Cup Series season and the 35th iteration of the event.

[2] Jeremy Mayfield of Evernham Motorsports would set the fastest time in the session, with a lap of 37.352 and an average speed of 192.761 miles per hour (310.219 km/h).

[2] Jimmie Johnson of Hendrick Motorsports would set the fastest time in the session, with a lap of 29.209 and an average speed of 130.398 miles per hour (209.855 km/h).

[4] The third and final practice session, sometimes referred to as Happy Hour, would occur on Saturday, August 21, at 11:10 AM EST and would last for 45 minutes.

[2] Elliott Sadler of Robert Yates Racing would set the fastest time in the session, with a lap of 29.209 and an average speed of 130.398 miles per hour (209.855 km/h).