If your map sensor is bad it can cause your engine to run too rich which would cause black smoke to come out of your exhaust.
Also check to make sure the hose is connected to the map sensor because that happened on my truck once.
The vacuum hose that connected to the map sensor on my truck came off and was causing the engine to idle rough and stall and run rich.
I suddenly noticed black smoke coming out of the exhaust and couldn't figure out why and then I looked around in the engine bay and found the map sensor hose to be disconnected.
It just vibrated loose and I had to put some sealant on the hose to keep it from coming off.
It hasn't happened since I put the hose back on.
Driving with a bad map sensor is not recommended as it can cause engine running problems and cause engine stalling, and cause your vehicle to use more fuel mileage.
So replacing the map sensor is highly recommended so that you have a good running engine and don't use more fuel than you normally would.