Muniz's career in car racing traces back to 2004, when he ran the Toyota Pro/Celebrity Race in Long Beach as a celebrity participant, finishing 7th. The following year, he finished third, and was the best-finishing celebrity after capitalizing on Ingo Rademacher and Aaron Peirsol's contact on the final lap. While investigating the possibility of joining a racing team as an owner, he was granted a test in a car, and instead signed a two-year deal with Jensen Motorsport as a driver. Muniz entered fourteen races during the 2006 Formula BMW USA season, and failed to finish in a point-scoring position. He was selected as one of the thirty–six drivers to compete in the annual Formula BMW World Final at Valencia. Muniz finished 29th. In April, he again competed in the Toyota Pro/Celebrity, finishing 11th after starting 19th.