An Ohm Meter is your best friend! It was a crap shoot as to which one was bad.. they all were testing around 0.5-0.6 but the sixth one at first tested at about 0.9 for less then a second at first I all most didnt see it on the meter. Then it dropped to 0.6 then stayed around 0.5 then dropped to 0.4 and stayed there. even though the spec's says 4-8 is good the sixth one had a lower reading then the rest and the odd reading at first... I had my mind made up that I was going to put that coil in every position if I had to.....But I got LUCKY and hit the bad one the first time!!!!!