Why does the Audi A8 experience weak acceleration and vehicle shaking during sudden acceleration?
3 Answers
There is an intermittent connection issue in the wiring between the sensor and the engine ECU. Troubleshooting: Read the fault codes, but no fault codes were output. Measured parameters of various sensors were normal (with the multimeter probe grounded to the engine). After replacing the throttle valve assembly, the issue persisted. Suspected that there might be an intermittent connection issue in the wiring between the sensor and the engine ECU. The problem lies in the ground wire: Due to the inconvenient installation position of the computer, a new computer was used to connect the wiring harness for measurement. When measuring the sensor power supply terminal (Vc), the voltage was found to be only 3.9V (with the multimeter probe grounded to the body), significantly lower than the standard voltage (around 5V). However, when the multimeter probe was grounded to the engine, the voltage of the power supply line (Vc) for various sensors (such as the throttle position sensor and intake pressure sensor) was measured at 4.9V, which is normal. This indicates that the problem lies in the ground wire.
Having driven an Audi A8 for many years, I've encountered issues with weak acceleration and shaking, which are mostly related to fuel system problems, such as insufficient fuel pump pressure or clogged fuel injectors. Ignition system issues should not be overlooked either, as worn spark plugs or faulty ignition coils can cause misfires, leading to car shaking. I remember during one repair, the mechanic found severe carbon buildup in the throttle body, which affected air intake. A dirty air filter can also restrict airflow, starving the engine. It's best not to delay—take your car to a 4S shop or a reliable repair shop as soon as possible to scan for trouble codes with a computer. Otherwise, more parts could get damaged, leading to higher repair costs and longer downtime. Regular maintenance, like oil changes and carbon cleaning, can help avoid such headaches.
When encountering a lack of power and shaking during acceleration in an Audi A8, I always start by checking the simplest things. Worn-out spark plugs are the most common cause, and replacing them often solves the problem. Carbon buildup in the fuel injectors can also reduce fuel spray, leading to sluggish acceleration. You can try cleaning them with additives yourself or check if there are any loose connections. Once, my car had similar symptoms, and it turned out to be a faulty ignition coil—replacing it fixed the issue. However, this isn’t just a minor problem. Ignoring it for too long could lead to timing chain looseness or insufficient cylinder pressure. For peace of mind, I recommend regularly replacing the air filter and inspecting the ignition system. Don’t wait for a major breakdown to fix it—safety comes first when driving.
