Just purchased a 2012 International Terrastar (light duty commercial truck) from Washington State last month (Im in VA). We flew out to Washington to test drive and found no issues. Now, everytime the truck gets 'hot' we have some type of exhaust issue. Its usually around 45 minutes into a trip (not even pulling anything) the truck engine will get incredibly loud, it feels like we lose some power, and exhaust light comes on telling us the exhaust is hot. We hooked a reader up to it but it didn't come up with anything. The truck has a 6.4 Maxxforce 47 engine. I've searched high and low on the internet and cant find anything. Any ideas??