If your car suffering unstable idling, delayed gas pedal response, delayed acceleration, power loss during acceleration, fuel consumption increase significantly, it might be due to the alternator undercharge. An undercharge alternator mostly cause by below error:
1. Faulty fuel system. The fuel did not supply to combustion chamber via the supplying hose, making the engine work abnormally. If there is no sufficient amount of fuel send to combustion chamber to explode, it cause the engine power output become lower, mosty likely the root cause are injector is clogged, efficiency of fuel pump dropped, or the fuel filter is clogged. Suggest to diagnose at workshop.
2. Faulty intake system. Engine produce power through the process of igniting the air mixtures with fuel. If the intake system is faulty, the engine power output become lower due to insufficient air supply to the engine. Most of the time a faulty intake system cause by air filter or valve clogged. Suggest to diagnose at workshop.