After washing the car and heading out for a drive the "Check Engine" light came on solid. I thought maybe I got something wet during the washing (which is mentioned in the owners manual as a possible cause for the check engine light) or that maybe the gas cap wasn't securely fastened (which has caused this before). Turns out the "EXT CMP Solenoid Actuator (Valve)" part number 12628348 needed to be replaced (covered under the extended warranty). That seems to have resolved the issue. Just posting to add to the body of knowledge on this subject.
Envious / Ebony Leather / Manual Transmission / Touren Wheels
All Options Except: On-Star, Premium Headliner, 6 CD Changer
Fujita CAI, SOLO Performance Shorty Header/Ultra High Flow Converter/CAT Back Exhaust Kit, DDMWorks ProBeam/Backbone Brace/Venom Brace, Z0K Front/Rear Sway Bars, Stage 1 Brake Kit, Short Shifter
Other Vehicles: '72 Opel GT, '99 Oldsmobile Intrigue GLS, '09 Pontiac G8 GT