I have a 2004 Santa Fe W/ 3.5L V6, It has 15500 miles on it. Up to now there has been no problems with it. I am using Mobil 1 5W30 with Hyundai oil filters. The other day When I started it there was a lot of noise coming from I believe the valve train also it was running real rich, I could smell the unburned gas. This went on for about 30 seconds then cleared up and has not happened again. When I test drove a Santa Fe before buying mine that car had the same noise coming from the engine only it did not go away. The salesman said some of the vehicles have that problem and something there shop does to correct it. Has anyone run into this problem. Lifters leaking down ? Striker