In 2007, Muniz moved up to the more competitive Champ Car Atlantic Series, where he competed in the entire season of 12 races. For the season, his best race finish was ninth place, and he officially earned a total of 41 points (for 22nd place) and $17,000 in prize money, logging 351 laps. In January 2007, he placed second at the Sebring Winter National race. He signed with Atlantic Championship-winning team Pacific Coast Motorsports in January 2008, with a goal to consistently compete in the top ten of the points championship. He finished the 2008 season in eleventh place. At the end of the 2008 season, he won the Jovy Marcelo Award, an award for sportsmanship voted on by fellow drivers named in memory of the 1991 Atlantic Championship winner who was killed during practice for the 1992 Indianapolis 500. In 2009, Muniz joined Team Stargate Worlds, and finished in the top ten in every race he contested, with a best finish of fourth at Miller Motorsports Park. However, prior to the penultimate race at Road America, his season was shortened by wrist surgery.