Started my tahoe to drive home and i'm going 70 mph down a highway when all of a sudden my engine light pops on and says engine power is reduced plus it says service traction control and service stabilitrak. i went from 70 mph to 20 mph in less than 5 seconds and now my tahoe is sputtering and has no power. the whole vehicle is vibrating. i've shut off the vehicle multiple times and i can't get the error to go away. sitting at an idle my rpms fluctuate consistently. unknown but i have a feeling that the throttle body is going out on the engine, it would be the only thing i can think of that would cause the engine to drop speed and sputter like this non stop.