Rusted Wastegate Actuator Cars affected: Evo 4-6 (possibly earlier Evo's and the Evo 7) Symptom: Lack of boost or excessive boost levels with possible fuel cuts. It can be intermittent or erratic. Problem and cure: The location of the Wastegate Actuator and angle of the actuator arm promotes water entering the Actuator diaphragm assembly. This can lead to early failure of the actuator due to rust build up. Early symptoms maybe hard to spot without a Boost Gauge fitted. The only cure is to fit a new Actuator. The fitting of an aftermarket actuator of different design should prevent any further problems. Approximate cost of repair: A new Wastegate Actuator is approximately £200 inclusive (plus fitting approx. 1 hour). Back to question page