Illumination of the Check Engine Light can be caused by a loose or worn gas cap.
Average mileage: 87,875 (35,000–189,000)
21 people reported this problem
Was on the freeway. Lost almost all power/acceleration. Pulled off freeway and called dealer. Check engine light was on. Car lurched along when trying to go. Dealer said maybe gas cap was loose. Opened gas cap, turned tightly to hear three audible clicks, then started and stopped the car 10-12 times (per Dealer instructions) and the problem went away. Same thing happened to my sister's 2000 Denali. Same solution worked.