I own a 99 Audi a6 Quattro when I try to drive my car it will not accelerate and

P1545 Throttle Position Control malfunction P1857 ECM Load Signal Error P0303 Cylinder Number 3 misfire detected (Replaced already) P0102 MAF Sensor Circuit Low input But changed spark plugs, and MAF sensor and now the car won't stay idle. Help!