If you want to know how the engine is running at wide open throttle, you'll have to make a full throttle run, then cut the engine right after you let off the gas. If you don't, the plug will get all carboned up from idling around and will look rich.

As for how to read plugs... go to this EXCELLENT website.

http://cochise.uia.net/pkelley2/sparkplugreading.html

Good Luck!
[addsig]