I recently purchased a 2007 Dodge Charger SE with 26,000 miles. It has 2.1 Liter DOHC engine. When I drive the car between 30 and 40 mph and take my foot off the gas the car shudders slightly. It also happens when I take my foot off the gas when going up a hill and the car slows down at a speed between 20-40 mph. The shuddering totally stops when I accelerate. Other than this the car drives great.