[turbo23dog]

Let me offer a few scenarios as to what I believe it means to lug the engine.

Lets say you floor the car off the line in first gear. The engine will move the car forward in a happy manner. Now floor the car off the line in 4th, 5h, or even 6th gear. The engine will not sound happy and in my mind is akin to lugging the engine.

Here's another scenario: have the car in 6th gear as you brake for red light. Don't press the clutch in, just use the brakes... the engine will not be happy at anything less than about 15 mpg heading toward zero... that's lugging the engine. This also gets back to flooring the car in 6th without shifting to a lower gear to accelerate should the light turn green... that's lugging the engine.

So I believe that in the context of the above, as a happy medium between lugging the engine and driving it like you stole it, avoid mashing the gas pedal in a higher gear when under 3K rpms to keep the engine happy. Use a gear appropriate for the speed you are going, as well as how much you are accelerating.