Question: When coming to a stop...?

Could be Dirty Injectors......or even bad valve seals!

Try some seafoam to get rid of some of that possible carbon coming out...I have heard good things about it.

Anyways, I use my brakes because they are meant to stop the car (not the engine)...that does the opposite.

Plus brake pads are much cheaper and easier to maintain than an engine rebuild

The only time I down shift is when I want to hear the unburnt gas burn off in the mufflers...

If your brakes are going then I could see using the engine to help out, but if you have good brakes you might as well use them.

Cleaning the fuel system is always a good idea but will not cure your problem. In fact, it may be incurable.

What is happening is that when you are downshifting with the throttle closed; you are creating a lot of vaccume which is sucking up oil through your PCV system which goes into your intake. Small amounts of oil will go into the combustion chamber right away, when you hit the gas, the blast of air blows the rest into the combustion chamber, making lots of smoke.

Check your PCV and pull the screne. It could be stuck open or saturated. For the price, why not replace if you have not recently done so?

-EDIT-ADD- You may not be able to cure this problem if piston-ring blowby is excessive. That would overload the PCV. Some have installed a catchcan between the PCV and Intake to catch the oil.

i just use my brakes