Lugging occurs when the engine RPMs drop and the torque increases.

• A. When the engine RPMs drop and the torque increases
• B. When engine RPMs rise and torque increases
• C. When torque is constant regardless of RPM
• D. When the engine temperature rises

Answer: (A)

Lugging happens when the engine is asked to produce a lot of torque while running at a low speed. In a heavy-load condition or in too high a gear, the RPMs drop but the torque demand increases. Since horsepower is limited by engine speed, the engine can’t keep the speed up as the load grows, so it strains and tends to stumble or overheat. The scenario described—lower RPM with higher torque demand—best matches lugging. If RPMs rise with increasing torque, the engine isn’t lugging; other cases like constant torque or rising temperature alone don’t define lugging.