my truck has a knocking noise. i'm pretty sure is in the valves. the truck is a 91 3.0 v6. the question i have is; has anyone had one of these trucks make a light knocking noise not when idling but starts at about 1500 rpms and then stops when you get above 2800.... ?? another thing is that it doesn't make the noise when there is any stress on the engine like up or down shifting or driving in general just when you rev it up slowly. any imput on what the problem was on your rig or might be here would be greatly appreciated.