* 2.5L 4-cylinder: This engine produced 175 horsepower and 175 lb-ft of torque.
* 3.5L V6: This engine produced 250 horsepower and 249 lb-ft of torque.
To know exactly which engine your specific 2006 Nissan Altima has, you'd need to check the vehicle identification number (VIN) or consult the owner's manual.