Black smoke is a sign of an overly rich fuel/air mixture. This will eventually ruin your catalytic converter. The Check Engine light should be on. Are you sure the light is actually working and is not burned out. Turn on the ignition and see if you see the light. If not the bulb is burned out and needs replacing. On a 22 year old vehicle this would not be uncommon. I would first check the fuel pressure at the schrader valve in the fuel rail. There should be approx. 35- 40 psi with the engine at idle. If the pressure is higher, the regulator is leaking. A constant fuel pressure drop is maintained across the injector nozzles by the pressure regulator. The regulator is connected in series with the fuel injectors and positioned downstream from them. Excess fuel supplied by the pump, but not required by the engine, passes through the regulator and returns to the fuel tank through a fuel return line. The regulator is a diaphragm-operated relief valve in which one side of the diaphragm senses fuel pressure and the other side is subjected to intake manifold vacuum. Alot of times, these would fail causing high pressure. Remove the vacuum line from it and see if any fuel is present. Another possibility is the mass air flow sensor located in the air tube inlet from the air cleaner to the throttle body.They can also give this symptom. Try disconnecting the electrical connector from the sensor while at idle. If it's faulty, it will usually make the engine smooth out. A scan test should also be performed to check for any fault codes related to the poor running condition.

Air temp sensor?? You mean coolant temp sensor. If not, do that.

Hi so what do you expect from an old worn out clapped old engine new engine performance.

Foul air filter, blockage in air line - something getting hot and distorting.