Question: When coming to a stop...?

[cjman15]

...Do you downshift and let your motor slow you down? ...or do you use more of your breaks to stop?

I usually downshift and coast before I get ready to stop, but lately, when I downshift (usually into 3rd) it'll be taching around 2000-2200 before I start to brake and I notice a small bit of smoke out the back... then, If I hit the gas, a big puff will come out... I don't see smoke like that any other time I drive it... what could it be from?

 

[DJTR]

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

 

[cjman15]

injectors can't be dirty... just put a bottle of 44K thru it...

 

[5spd GT]

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

 

[srothfuss]

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.

 

[90mustangGT]

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.

 

[super302]

i just use my brakes