2000 Dodge Durango P0171 P0551 P0455 P1195 Fault: Poor Fuel Economy, Black Smoke, Exhaust Soot - How to Fix?

I own a 2000 Dodge Durango with a 4.7L V8 engine. The vehicle runs smoothly under normal conditions, but it consumes fuel rapidly—averaging only 7 to 8 miles per gallon. When the engine is revved, black smoke is visibly emitted from the exhaust pipe. A code reader shows multiple diagnostic trouble codes: P0171 (Rich Air-Fuel Mixture Bank 1), P0551 (Fuel Level Sensor Circuit Malfunction), P0455 (Evaporative Emission System Leak Detected), and P1195 (Exhaust Gas Recirculation (EGR) System Failure). I have inspected the vehicle thoroughly, including vacuum hoses—no obvious damage is visible from a beginner's perspective. Upon inspecting the oxygen sensors (before and after the catalytic converter), I noticed black or oily residue seeping down the exhaust pipe near where the sensors are mounted. The sensor wiring appears dry and intact. This suggests potential issues with fuel delivery, combustion efficiency, or exhaust system leaks. The vehicle also has an unrelated issue: the blower motor is completely non-functional, even at high speed. I suspect this could be due to a faulty resistor pack. Can anyone confirm if replacing the resistor pack would resolve this? Any expert advice on diagnosing and fixing these issues? Thanks, Andy