Cobalts are notoriously known for their warped rotors some striaght from the factory with as low as 23k on them. Also they can warp from heat dissipation or if they are real hot from driving and you get water on them this will cause hot spots as well. Some rotors can be machined and get the hotspots out but that depends on if your rotors are still withing spec of being machined or not
Mod's So Far: AEM CAI, C.A. Header, 2.50 Magnaflow Catback Exhaust , ZZP Catless Downpipe, DC Carbon Strut Bar, Dropped on Progress Springs. Tinted, Fully Debadged, Custom front SS bumper,2 Audiobahn 10" w/JL amp, Lower Billett Grille, Sengen 18 x 8 rims wrapped in Capitol Sport UHP 225/40/18.