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.Google+
Car Problem Reports
Mercedes-Benz 600SEL Faulty Mass Air Flow Sensor Causing Erratic Engine Operation and Poor Fuel Economy
Mercedes-Benz 600SEL Problem
Average Mileage: 136,000 mi (135,000 mi - 137,000 mi)
running rough, black smoke exhaust, no power, 45 .mph top speed, replaced.
Visitor, 1993 Mercedes-Benz 600SEL, 135,000 mi
mass air flow sensors allowing too rich a fuel mixture causing engine to run rough when warm. replaced mass air flow sensors. Dealer price near $1,500!