I have been doing alot of reading on doing home brew ecu tuning, and the more I read the more Im interested in giving it a shot. But I also have questions. What is a map trace and why is it important? I notice sometimes this feature doesnt work depending on what piece of software you are using.

Map tracing lets you know exactly where you are in the map. that way you know exactly where to make your adjustments

you can buy hardware to do it for you anywhere on the eprom, grid do a nice compact one