Chevrolet HHR check engine light on with gas fumes odor and muffler issue on Chevrolet HHR

Some Chevrolet HHR owners report experiencing issues when the check engine light is on, accompanied by a gas fumes odor and potential muffler problems. These issues may arise from a leak in the exhaust manifold, which can create a lean condition by allowing air into the exhaust system. A flashing check engine light could indicate a serious misfire, risking damage to the catalytic converter due to raw fuel entering the exhaust. Additionally, the smell of gas may stem from poor engine performance, with factors such as shrinking hoses or a malfunctioning fuel pressure regulator causing excess fuel in the system. A faulty gas cap can also contribute to gas fumes by allowing vapor to escape when its seal deteriorates. Owners are advised to investigate the underlying causes of the check engine light and inspect related components to prevent further damage to the vehicle.