I have a new Frontier SE 6 Cyl. I really like it. Gave up a Tacoma that I was not satisfied with. Question, I have experienced no problems with the truck. Have had it for about 3 months. What I notice is when started cold, there is a quick 2 or 3 second grinding noise coming from under the hood. Cannot say it is the engine or anything else becuase it happens so quick. If parked at work during the day, started, no noise, only when sitting in the garage over night. I live in central CA, so cold is definately not an issue. It cools down each night maybe to 60 degrees. What do you think ?