I believe this is a 4.9 L engine ,correct?
Start by seeing if there are any trouble codes stored in the ECM.
You can do this by turning on the ignition and pressing down and holding the off and warmer buttons on the climate control at the same time.Write down any codes stored .There may be a code that can give you a clue as to whats happening.
For some reason,the computer is adding more fuel ,causing the odor,black smoke.
The black smoke is indicative of a rich fuel mixture(too much fuel).
For laughs,take the vacuum line off the fuel pressure regulator and see if there is any fuel present in the line.There should NOT be any fuel in the vacuum line.If there is ,the pressure regualtor is faulty and needs to be replaced.
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