2006 nissan pathfinder starts then stops and blows black smoke

Get the suspension springs checked. Park the vehicle on a flat, level surface with no-one in it. Stand back and carefully look at the vehicle. Sometimes when a spring fails the vehicle will lean towards the broken side. The tail ends of the spring can break off when they are old and the broken bits don't always fall out when it happens.
The stall could be something separate. Do you have any warning lights on the dash? If the charcoal canister is starting to fail it often causes the check engine light to turn on as it will affect the emissions. This will trigger other engine sensors to flag up a trouble code.

Black Smoke is unburned fuel, try a tune up to start with and replace the air filter. If it does not stop then check the injectors to make sure that one or more are not stuck open.

there is a very common issue with bad distributors in nissan pathfinders,xterras.and quest. just replace the distributor

White smoke is ok on starting. Changing the engine oil and air filter should do it.

check your spark plugs, injector nozzles, fuel pump and the type of fuel in your car.

to keep up the concentration of a/freeze use neat.the symptoms you mention are conducive to low water/an airlock in the heater system.

Does it overheat at all?

White smoke? or Dark grey smoke?

Could be Oxygen sensor (grey) or head gasket (white).

Vacuum line

tyre a air flow meter

Your truck is fuel injected . Black smoke indicates a rich fuel mixture. This could be caused by numerous items. A faulty sensor, a faulty injector, a misfiring spark plug are some of them. To really zone in on the problem, a computer diagnosis is required to note sensor readings, and repair as necessary.