A Loose or worn gas cap may cause Check Engine Light to illuminate.Google+
Car Problem Reports
Pontiac Solstice GXP Check Engine Light Due to Gas Cap Issue
Pontiac Solstice GXP Problem
Visitor, 2008 Pontiac Solstice GXP, 60,000 mi
Gas fumes in the interior of the car. No system alert light for several weeks. No signs of gas leak. No exterior smell.