There are all sorts of interesting information that can be gained by looking at ignition timing retard/advance. I have scangauges and USB OBD II scanners, but I do not necessarily understand how to read it. I assume when it tells me that IGN is 35 degrees, that is compared to TDC, but it is not clear what the advance/retard is for a specific operating point, load, and use. For example, if I am cruising at 65 MPH on flat ground with no wind, and it tells me 35 degrees or 33 degrees, what is better? What is right? CZan advance go too far? How do I really use this data? It seems that I can optimize on fuel, spark plug life, etc. by looking at this. But when giving a single value number that is "degrees", how do I use it? Thanks!