Lugging is pretty much what is sounds like, Judy. If you’re lugging an 80-pound prize-winning rutabaga up your stairs, that implies you’re dragging it, and struggling to get it done.Similarly, lugging the engine refers to trying to accelerate when you’re in too high a gear. So put most simply, you’re straining the engine. You’re making it struggle.Imagine if you were on your 10-speed bike, and you got to a steep hill and tried to climb it in 10th gear. You’d be struggling and straining, too, and you might even “stall.” That’s because, like your car’s engine, you’re not using the mechanic advantage that the lower gears are designed to afford you.And when the engine is struggling — when it’s trying to move the car, but can’t get up to an engine speed where it can turn easily — it will begin to overheat.t’s not the kind of catastrophic overheating, like when you see steam coming out from under the hood. But when you lug the engine, you’re making the cylinders and pistons run hotter than they normally would. And over time, that damages the engine.