Well, the truck has 174,000 and runs very good except for the occasional rough idle which I think is normal. I bought it with 152,000 from the second owner who had it since 102,000. I know for a fact that he did not have the valves adjusted during his ownership and I havent either. Who knows if the original owner did it. If you ask me, I would say it's never been done since new. I have talked with one of my local dealers that I trust and was told adjusting them would only quiet it a little and why waste the money since it wont affect the performace or longevity of the engine. Basically they wont do it even though its reccomended. I'm sure you guys will have comments about that.