The rash of engine-related problems for Joe Gibbs Racing continued Sunday at Phoenix International Raceway.
A broken valve spring necessitated an engine change on Kyle Busch's No. 18 Toyota. This follows an engine change for Denny Hamlin that was made on Saturday prior to final practice for the Subway Fresh Fit 500.
And this comes a week after Busch and Matt Kenseth exited the Daytona 500 as a result of blown motors. Kenseth was leading when his engine started smoking, while Busch had been running in second.
Toyota Racing Development, the builders of engines for JGR as well as Michael Waltrip Racing, determined Kenseth's failure was due to a bearing issue.
Busch and Hamlin will both have to start at the rear of the field Sunday. Busch had qualified fourth, while Hamlin would have started eighth.
Toyota has been the dominant manufacturer throughout the Phoenix weekend including Mark Martin winning the pole Friday. But in an effort to preserve the number of laps on his motor, Martin completed just seven laps in final practice. And in an interview with Speed Sunday, Martin cited "reliability" as his biggest concern.