In 2004 he matched or surpassed several of Broncos Hall of Fame QB John Elway's passing records (including passing yardage and passing touchdowns in a single season). In a game 1 win against Kansas City, he reached 20,000 career passing yards. In game 8, he threw for a spectacular 499 yards and 4 touchdowns against Atlanta. However, continuing a career-long shortcoming, he also threw three interceptions in the loss, and led the league that season with 20. He led the Broncos to a second straight wild card playoff berth, but the Broncos were again beaten by the Colts 49–24, despite Plummer's 103.1 passer rating in the contest.