Service Engine Light On problems of the 2009 Chevrolet Tahoe

My Tahoe will jerk backwards really hard. Then I get error messages stating the "stabilitak has malfunctioned" "traction control off" "service engine" and last but certainly not least "reducing engine power". I cannot go over 15 when this happens, which makes it really hard to get off the road when this is all happening. The whole vehicle bucks back and forth wildly as the cyclinders are shutting down. This is a terrifying experience since I have 2 small children in the car with me. Now my car is not safe to drive. If I do try to drive it it grinds and makes horrible noises and the service engine light is now permently illuminated on my gauges. I cannot turn the vehicle with out it completely stopping. . . On its own. . . My foot will still be on the gas. Also it accelerates on its own. . . We live in nd and get tons of snow and ice. This thing is a death trap. I have purchased a vehicle that I cannot drive. . . But still must make payments on. It is a total lemon!.