High consumption (Solution)

In TDIs with a VP37 injection pump, if the injection timing is incorrect (due to an improperly set base setting or a faulty adjustment mechanism) and/or the injectors are worn, the fuel will not be used efficiently.
A heavily soiled air filter not only leads to increased soot production but also increases fuel consumption. Similarly, leaks in the charge air system (caused by rodents, cracks, or chafed hoses) can cause problems.

Hello Rainer, a faulty mass airflow sensor (MAF) can also lead to increased fuel consumption, as the accelerator pedal is often pressed more to demand more power.