You cant rely so much on the A/F meter alone during tuning. Instead, a knock monitor toy should be working hand in hand with your chosen A/F meter.
J&S
http://www.jandssafeguard.com/
MSD
http://www.msdignition.com/tool_8.htm
HKS (Old Model)
http://www.autodesignhaus.com/tuners/hks/ipm.htm
The latest HKS A/F Knock Amp has both capabilities of a A/F meter and Knock Monitor. Apexi Power-FC has knock meter on its handheld commander.
So far the best knock monitor i think would be the :
http://www.theknockbox.com.au/
I believe by listening and looking at the pattern using a software would help even better to detect knocking.
