I put this here because I like to change oil and consider one of my hobbies. This is a friend of ours from church. It is a 2003 Suburban with the 5.3. All original drive train. Only problem he is having is it will go into limp mode. He turns it off and starts it back up and it is fine for a while. Also it has an oil leak. A little worse than normal but he said it only uses a qt of oil in 3k miles so I don't think it is to bad. The other thing is this thing has seen a rough life. Oil changes were ignored before I started doing them two years ago. He also ran what ever oil was the cheapest in it. He still does with me. But I get my non AMSOIL oil at a major discount as you have seen in a previous post about Auto Zone. So I have been running Mobil 1 in this for the past year. Considering it only cost me $2 a qt I pass the savings on to them. Just thought you guys might be interested.