A faulty mass air flow (MAF) sensor can cause erratic/rough engine operation and fuel economy issues. Since this sensor measures the actual amount of air entering the motor, when it fails, the engine control module (ECM) takes the wrong information and delivers incorrect volumes of fuel to the cylinders.
Erratic Engine Operation and Poor Fuel Economy Due to Faulty Mass Air Flow Sensor on Mercedes-Benz SL320
Average mileage: 98,000 (98,000–98,000)
5 people reported this problem
Runs rough at idle mostly and uses huge amounts of fuel all of the time