In 1984 Holmes joined Mayer Racing to drive the No. 41 Jiffy Mixes March 84C-Cosworth DFX. The season started off well as Holmes finished second to teammate Tom Sneva at the Dana Jimmy Bryan 150 at Phoenix International Raceway. Holmes then qualified second to Sneva at the Indianapolis 500. Holmes' car suffered mechanical problems throughout the race and Holmes finished 13th, 15 laps down. The rest of the season brought some more points finishes, although none were as good as Holme's early season form. Holmes finished the season 12th in the CART points and unranked in the USAC points due to scoring no points at Indianapolis.