The Pilot's Manual For Leaning & Diagnosing Engine Problems
I found this article about leaning and found it very interesting and informative. I posted in another leaning thread, but I think it is important enough to be able to find quickly and print it out, so I started a thread of it's own. There are good diagnositic tests you can run and forms to record the results. Having a base line of information on your engine can help figure out when things need attention.