Mine had pitiful airflow. I could hear the motor running on full but no airflow. I thought the blower must've separated from the motor. I removed the glove box and stuck my hand in there(without the motor running). I put my hand in what was left of a rodent's nest. He had taken a roll of paper towels I had in the back and converted them into a nest in the middle of the squirrel cage. It wasn't messy or smelly so I guess he never had a chance to live in it. But I would've given anything to see the look on his face when I turned on the motor. A shop vac made short work of the mess and it's been working great ever since. Probably not your cause of restricted airflow
Mike