Hunter-Reay began to drive for Herdez Competition in 2004 in the #4 Herdez Lola B02/00-Ford Cosworth XFE. In the third race of the season, the Time Warner Cable Road Runner 250 at the Milwaukee Mile, Hunter-Reay would qualify on the pole position and lead for all 250 laps to get his second and final Champ Car win. Following the race Hunter-Reay was ranked third in points. Hunter-Reay's best finish in the remaining races was a 4th at the Grand Prix of Road America presented by the Chicago Tribune at Road America. In the race Hunter-Reay started second and made contact with former teammate Jimmy Vasser on the first lap and dropped the two to the rear of the field. Hunter-Reay charged up through the field to get fourth place while Vasser finished eighth. Hunter-Reay would finish ninth in points (the only time Hunter-Reay finished in the top 10 in points in Champ Car) with 199 points.