What could be causing my Audi 80 to struggle at high speeds?

I have noticed that my Audi 80 starts to struggle and lose power once I reach high speeds on the highway. What could be causing this issue?

It is possible that your air filter or fuel filter may need to be replaced. These components can become clogged over time and can affect the engine's performance.

Another potential cause could be a malfunctioning oxygen sensor. This sensor monitors the amount of oxygen in the exhaust and can impact the engine's fuel and air mixture if it is not functioning properly.