I added a PC3, borrowed a lap top and loaded a new map on mine. If I'm not mistaken the ability to richen or lean was there for the three stages. Idle, mid-range and full throttle. I don't understand all I should so I havn't experimented.OK, I just found my PC3 instructions and it definantly explains how to lean the mix.The model I got was the PC3 USB. Which I think the only difference is it comes with the adapter to power the PC3 with a 9volt battery and a USB connector for your computer.Hopefully someone else will chime in that has a better understanding of how it all works. Mines not perfect yet but I'm not the one to be toying with it. I hope to get a Dyno someday.Good Luck!Bill
sorry i missed quoted the $500 bullet