Mitch offered to help.
In 1993, she borrowed a stock Miata, a Mazda Navajo SUV and a trailer and bought new tires for the Miata.
"I collected all these things and showed up at Willow Springs," she says.
The Sports Car Club of America ran Miata races at Willow Springs International Raceway near Rosamond, Calif., as part of its showroom stock series. McCullough also raced in Phoenix and the old Holtville Aerodrome International Raceway circuit near Holtville, Calif.
She learned fast, finishing second in the Sports Car Club of America championship at Holtville in 1994.
"I loved that track. It was a hoot," she says.
Was she afraid? Not at all.
"In an odd way, it was relaxing," she says. "You are out on the track and that is all you think about."
Being one of the few women at the track didn't matter. McCullough says the racing community was extremely supportive.
Kim and Mitch married in 1994, the same year she left Mazda. The pair moved around as McCullough took various advertising agency jobs and then went to Land Rover in Annapolis, Md., in 1997.
By 2005, with Kim heading communications, advertising and marketing for Toyota Division in the U.S., the McCulloughs had returned to California and decided to get back into racing.
This time, though, they chose to race vintage cars. They bought a silver 1956 Alfa Romeo 1900 CSS coupe and raced it for a few years in 1,000-mile, three-day vintage competitions. Their first race was in 2007, the California Mille, for cars built in 1957 or before.
"The object was to finish," McCullough says. "When you have older cars there is victory in finishing."
The husband-and-wife team took turns driving the route that started in San Francisco and wound through picturesque northern California. The McCulloughs completed three California Milles.
In 2007, they competed in the Copperstate 1000 in Arizona, which allowed cars built as late as the mid-1970s. They raced a 1972 Alpine A100 and completed the first race. But in their second year in Arizona the car "finished on a flatbed -- we had a catastrophic failure," she says.
"The first year we got an award for being the most willing participant with the most unwilling car," McCullough says. "The Alpine had so many problems but we always got it going again."
The couple moved east again in 2011, when Kim became brand vice president for Land Rover. She says, "We set our sights on the Mille Miglia."
In 2015, they entered the famous 1,000-mile race, which starts in Brescia, Italy, goes to Rome, and returns to Brescia.
"That was a big undertaking," she says. "When you run an event overseas there are logistics involved and financial planning. It takes a bit of time and you want to save up and be prepared."