I purchased a 2007 GMC Sierra new . This truck has the V8 324 motor quad cab, short box. Since i purchased this truck i have had a major issue with the oil usage. I run full synthetic oil in my truck. GMC dealership told me to run my truck until the check engine light comes on or until my next oil change. I have burnt 2 to 2.5 qts of oil in 2200 miles and service is at 5000 miles. My dealership is the only one that changes the oil in my truck. The truck has 52000 miles on the motor, and has been burning oil for over 2 years now. The entire time GMAC has done nothing other than send me a customer survey email regarding this issue. I purchased the Extended warrenty and so far i have been blown off by GMAC regarding this major motor problem. I am curious if anyone else with this truck or the same motor has had the same issues that i am currently having. If so what has GMAC done for you if anything. Please respond to this post regarding this issue if you have experienced this problem.