I just a 2006 Titan, we are a week in and topped off the oil and filled the gas tank the day we got it. Now a week later the temp gage started reading a little high. My husband checked the oil and we are two quarts low. So in a week we used two quarts we have no leaks and there was just a tiny amount of smoke at start up. We went back the dealer where she in return called a Nissan mechanic who said for us to use a bottle of motor flush and change oil. Followed by 2-3 more oil changes over next 2-3 weeks. We did the first oil change today and now she smokes when starting and when we rev the engine which it did not do before. Our next step is to change the pvcs. Help! Why is it smoking now?