Carter raced at Long Beach, Indianapolis, Milwaukee, Portland, Cleveland, Michigan (both), Pocono, Sanair, and Phoenix. Moreno raced at Meadowlands, Road America, Mid-Ohio, Laguna Seca, and Miami. Buick engine for Long Beach and Indianpolis only.
A March 84C was raced in the first six races, and a Lola T900 was raced in the remainder. Firestone raced the car in the first 13 rounds, Bigelow relieved Firestone at Michigan (1), and Crawford raced the car in the final two rounds.
Roe at Long Beach, Indianapolis, Portland, Meadowlands, Cleveland, Gehlhausen at Milwaukee and Michigan 1, Mansilla at Road America, Mid-Ohio, Sanair, and Brayton at Laguna Seca, Phoenix and Miami. Lola T900 at all races except Sanair. Living Well sponsorship at all races except Long Beach. SPA*erobics at all races except Indianapolis, WTTV at Indianapolis only, and Autostyle at all races Brayton drove.
Buick engine at Indianapolis and Milwaukee, Dreisbach & Sons sponsorship at Long Beach and Michigan (2), Hardee's sponsorship at Indianapolis and Milwaukee, and Jolly Rancher sponsorship at Portland, Meadowlands, Cleveland, Michigan (1) and Pocono.
Mario Andretti dominated the first half of the season before breaking his collarbone in a crash during the Michigan 500, the first accident of his career that would force him to miss a later race. Andretti missed the race at Road America and was replaced by another former World Champion (1980) Alan Jones of Australia. Jones, who a month later returned to F1 with the Carl Haas owned Haas Lola team, finished third in the only IndyCar start of his career.
In the Sanair race (Molson Indy Montreal), Roberto Guerrero had a strong lead until he lost control and spun. Late in the race Jacques Villeneuve collided with leader Bobby Rahal in attempt to challenge for the lead, taking both out. The race finished under a yellow flag, but the safety car entered pit lane on the final lap, and thinking there would be a final restart, Pancho Carter passed Johnny Rutherford after the safety car entered pit lane and before the finish line. CART initially declared Carter the winner, but an appeals panel later overturned the decision and confirmed Rutherford's victory. In many codes of motorsport (typically FIA Code) the safety car enters pit lane as the field is on the final lap, and the cars cross the checkered flag together without the safety car on course. However, this practice is not accepted in North America, where the safety car leads the leaders to the finish line if the safety car situation exists.
Al Unser, Sr. won the season championship. Unser drove primarily in a substitution role for Penske's regular driver Rick Mears, who was recovering from leg injuries suffered in 1984. Mears ran only a partial schedule including the Indy 500 and a few other oval events.
Going into the final race of the season at Miami, the father and son duo of Al Unser, Sr. and Al Unser, Jr. emerged 1-2 in the championship points standings. In the closing laps of the final race, Danny Sullivan was leading, with Unser, Jr. in third. Roberto Moreno was running 4th and Al Unser, Sr. was fifth. As it stood, Unser, Jr. was tentatively the points leader, but Al Sr. was charging. With a few laps left in the race, Unser, Sr. passed Moreno for 4th position, and at the checkered flag, clinched the championship by 1 point over his son Al Jr.