Why does the fuel consumption increase after replacing the spark plugs with Bosch ones in an Audi Q5?
2 Answers
Audi Q5's increased fuel consumption after replacing spark plugs is usually caused by excessive engine oil. Here are the details: Reasons for increased fuel consumption after replacing spark plugs: When replacing spark plugs, some car owners also change the vehicle's engine oil, which leads to increased fuel consumption. If the spark plugs are not tightened to the specified torque during replacement, it can cause gas leakage. As high-temperature and high-pressure gases slowly leak, the pressure in the cylinder decreases, resulting in higher fuel consumption. Precautions for replacing spark plugs: When using old spark plugs, efficiency is relatively low, and carbon deposits accumulate. Therefore, the ECU automatically adjusts to inject more fuel to ensure normal power output. If the spark plugs are replaced without disconnecting the power to reset the system, the engine continues to inject fuel in the previous manner, leading to increased fuel consumption.
Last year, I replaced the spark plugs on my Audi Q5 with Bosch ones myself, and the fuel consumption started rising rapidly. At first, I thought the new spark plugs had better performance, but after driving a few hundred kilometers, I realized something was wrong. Upon inspection, I found that the electrode gap was adjusted too wide during installation, leading to incomplete ignition, uneven air-fuel mixture, and poor fuel combustion efficiency. I recommend using a gap gauge tool to measure the normal value, which is around 0.8 mm, and not just focusing on the brand. Also, remember not to skip cleaning the high-voltage wires and ignition coils, as their aging can increase resistance and indirectly affect fuel consumption. In short, be careful when doing it yourself—installation issues account for the majority of such faults. Watch more video tutorials to avoid mistakes.
