so i have a few random questions, 1) on the 3.7l dropping valve seat thing, is there any rhyme or reason behind it, or is it just bad luck? i think from what i have read, that overheating can be a contributing factor. what about mileage? is a high mileage engine more or less likely to drop a seat? 2) i just replaced the O2 sensor in my KJ, i cleared the codes it had, so there is finally no more check engine light displayed. how long would it take for another code to trip the light if there is still another problem? sadly, i have never had a vehicle from the modern era that did not have a check engine light on.