This job sucked the first time on my 99' but the second time it got better. I gotta say, I had the problem when I bought it, changed all plugs and in stopped until just this past week. So, I am very fortunate and got 100k on a set of plugs. Is there a resistance test or other test that can be done on a COP when its removed to see if it needs replacing? I checked each and had 6ohms of resistance on each, yet one still needed replacing. I have replaced 4 so far over the life of the truck...#4 and #7 are by far the hardest to do...