Q: My Audi a4 1.8t keeps vibrating at higher speed what could be the issue

Among common possibilities for degraded acceleration are throttle body faults (electronic throttle controls, mass airflow sensor, torn air intake hose), worn out spark plugs, faulty fuel pump or restricted fuel system, and large vacuum leaks (including EGR malfunctions, PCV system, leaking intake manifold, leaking EVAP purge valve). A scan tool would be used to look at real time conditions within the engine (particularly fuel trim, etc.) and identify the root cause. Depending on the cause of the slow acceleration, there is a possibility it could be linked to the vibration you are experiencing at higher speeds. If there is no link to engine operating condition, generally vibration at speed is wheel/tire/suspension related. If you want both of these issues diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request a loss of power inspection/diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.