Sentence:  A manifold pressure <WSD>overboost</WSD> control is usually employed to reduce the possibility of <WSD>overboost</WSD> occurring. However, when <WSD>overboost</WSD> occurs, combustion temperatures rise, and detonation or preignition may result and cause serious structural damage to the engine. 
Meaning of the word marked with <WSD> tags:  The process of overboosting.