ive had hptuners for about a year now and got it to tune my 2008 silverado with a 5.3 and a cam but started using it on my 2002 2.2 s10 stick daily drive to get some gains out of it . ive been using the histograms for afr and starting to get that figured out . with the spark ive setup a historgram to see knock but ive added a good amount and its still not showing any knock. is that normal ?