Has anyone been told the engine "heads" were bad on their '08? The dealership just replace my entire engine @ 1000 miles because of this. The service Stabilitrak, Traction Control, and Engine light all came on. The next day it would not start. it was in the shop and they said said it had "several codes" and they're waiting to hear back from GMC. They called back and said they decided it would be easier and quicker to replace the entire engine!