I think you are thinking about the revolving door of the TRD program...from WikiI may be wrong but I also remember that part of the reason he lost his ride at KBM is because when his diversity money from nascar dried up he didn't have enough to keep the ride. (It was a long time ago, but I remember Kyle saying something about his future at KBM relied on getting diversity money from nascar)
Wallace was previously a development driver in Toyota's driver development program where he drove part-time for Joe Gibbs Racing in the NASCAR Xfinity Series and full-time for Kyle Busch Motorsports in the Truck Series. He then moved over to Ford and their driver development program and competed full-time for Roush Fenway Racing in the Xfinity Series. After competing in select Cup Series races for Richard Petty Motorsports in their famous No. 43 as an injury replacement for Aric Almirola, Wallace became a full-time driver for RPM in the same car when Almirola left the team, which was his first full-time ride in the Cup Series.