03, 4.3, 4X4 I was trying to find fuel leak in plenamn, had the plastic dome off and was hooking fuel lines back up so I could re-preassure system and the nut on the left side slipped from my fingers, (working outside cold fingers) and it is not to be found.
I rented a bore scope to look back thru the air passages and still could not find it, took off the lower intake manifold and used scope again to look at top of valves, still not to be found. Only 2 valves (3 & 6)were part open (just enough to see park plug) but not enough to allow nut to pass thru.
Have looked all over engine, frame and ground but still not to be found. Any ideas to try next besides pulling head?

Thanks

 

You could pull the plugs and take a look in each cylinder. My guess is that it wouldn't make it past the valve and is likely hung up in or near the accessory drive brackets.