First, lugging is when the engine is so low in its rpm band that it struggles to accelerate the car (because torque increases with rpm up to a modest point in the rpm range). It isn't merely a lack of power.

If you have an automatic transmission, it's impossible to lug the engine at 20 to 40 mph -- the engine just has to be going faster, unless the tranmission cannot shift down into the lower gears, and you're stuck in 3rd or OD (a.k.a., 4th gear) -- but I've never heard of that problem in the AW-7_ family.

If you have a manual transmission, you could only deliberately lug the engine at that speed in 4th (or 5th gear, if you have it), but the fault would be the driver's for not choosing a lower gear -- you can't blame the car for the driver's ineptness.

When you say lugging, I'm thinking that you don't actually have an engine that's lugging (in the technical sense), but rather that it just doesn't have any power -- perhaps it's fuel starved? That could be quite different.

You could have a failing fuel pump (can't deliver enough fuel), or a bad hose on the in-tank pump connection (this problem is noticeable when the fuel level in the tank is below 1/3).
Or you could have a bad AMM (air mass meter).
Or a variety of other things, such as a skipped timing belt, etc.

Why not describe the problem in detail for us -- rather than just saying that it's "lugging"?