One problem related to gas recirculation valve (egr valve) has been reported for the 2011 International Prostar. The most recently reported issues are listed below.
Purchased a used Prostar from International and it has been a lemon. International knowingly sold this truck with the engine, exhaust system default. Egr and egr cooling system continue to break down when in operation causing the truck to shut down while in operation and leaking fumes into the cab. The two times that it has shut down I was traveling in city traffic, thank god as I was traveling very slow. Giving me the opportunity to maintain control.