When Im driving over 20mph and I use the brakes to slow down it feels like the abs kicks in (shuddering/skipping/vibration in the pedal and car). The traction control also sometimes comes on when it definetely shouldnt and also at times it randomly fails and I get the service traction system light and the abs warning light. The previous owner said that he bought cheaper rotors so they heat up faster and cause the vibrations, but thats not it. This happens right away with barely any warm up time. Need new sensors? New breaks?

 

Could be sensors.... Take it to get the codes read when they turn on next time.

 

Sounds like a faulty wheel speed sensor and is a very common problem on gm's. The thing that sucks about abs is sometimes when theres a problem, theres not always codes. If you have access to a tech 2 I'd watch the wheel speed sensors on data while someone else is driving and find out which wheel reads 0 before the others while stopping. The one that does is the bad sensor

 

pull of the wheels n check where the sensor reads from any of those ribs r cloged they will give you issues

 

All wheels or just front?

 

to be safe if u have 4 wheel abs which i asume u do id do all 4