Don't be mad at us. (Robot Voice) Overboosting sounds like the wastegate or Diverter Valve/Blow Off Valve problem. If you had a leak it would not get a very high PSI. So I would imagine it would have to do with something letting the air out.

 

Dont get all offended when you leave out important stuff lol. So you know it overboosted, how high was the psi then? Everything we suggested is still relavant, but the more info we have, the better we can help you