black smoke out of tail pipes everytime i start it
 

my monte carlo blows black smoke out of tail pipes everytime i start it and sometimes while driving and i smell it inside the car when i turn it off. and keep in mind i just bought it so when i floor it to see what its got it cuts out like maybe it needs a tune up but my mechanic said it doesn't. It also shakes back and forth while im at stop lights sometimes. PLEASE HELP!

Hello and Welcome to the forum! :thumbsup:

Tell us a bit more about your car type, year, engine size etc. Lets see if we can get this figured out.

Check all vac hoses, fpr, and injectors.

Certainly sounds like its running too rich on fuel.

Its a 2001 monte carloo ss 3.8L v6. What's fpr? And what does it mean to be running too rich on fuel?

Means the engine is injecting to much fuel, likely one of the sensors is not working properly. Do you have a check engine light on?

It could be a Bad O2 sensor but then again you would have a check engine light on... Is it on?
If it is...Take it to your local auto parts and have them run scan.. (Its free) That should give you a good idea whats wrong with it.
It will give you a code ... that will indicate what the problem is.

But with all that black smoke..it will eventually clog the Catalytic converter which will be a whole other issue.
So, I recommend you get it resolved as soon as possible...

Fpr=fuel pressure regulator

If it's black smoke you may have leaky injectors.

If you're mistaking blue smoke for black it's probably worn valve stem seals and/or worn valve guides.

Yes the check engine light is on and what are valve stem seals and guides?