The camshafts have a machined slot at the end of each shaft, this indicates where the cam should be when the crank is at TDC before power stroke. It can also be used to make a cam positioning tool very easily. This was the case on a Ford Contour that was my wife's car. Both side by side cams had this slot that could be used to hold the cams in position when changing the timing belt.
So I had the time to day to make a holding tool, and tomorrow I will see if I can loosen the cam sprocket in order to reposition the cam. The slots should be parallel to the cylinder head as per this write up:
SOHC V6 Camshaft Timing - Ford Explorer and Ranger Forums "Serious Explorations"®

Look for the picture cam1.jpg

 

Thanks to Ron and Ranger Forums, the rough idle and "misfire codes" problem has been solved.
By carefully following Ron's advise on testing and referral to some excellent write-ups on valve trains and timing, my good old Ford Ranger is now running as it should.

The problem is confirmed as being the right side cam having slipped by one chain link.
This caused the engine to idle somewhat rough and set misfire codes, but ran well at any road speed with no codes.
The cam timing was one link late.
The repair did take a lot of time and patience, but it was all worth it in the end.
Because it was the right bank timing chain that jumped, I plan on replacing the spring loaded tensioner, in case the spring is weak.

Thanks again Ron for you help and interest.

 

Good work

Glad you got it figured out and fixed

Thanks for the kind words and posting how it was fixed

 

Running Great!

Well, today I took my first highway trip into town.
The Ranger really ran very well, and there is a big difference when on the road now that the valve timing has been corrected.
The truck requires less throttle to accelerate, and there is less up-shifting, so I expect I should now get better gas mileage.
The engine now idles smoothly and of course does not set any codes as before.

I realize I did not say how I managed to make the chain jump one link in order to correct the timing.
This is the cam for the right bank, and the sprocket is at the rear of the engine very close to the firewall.
The sprocket bolt is too hard to get at, so I decided to try to make the chain jump one link by removing the hydraulic spring loaded
tensioner in order to give the chain as much slack as possible. I then inserted a small round object of the correct size between the
chain and the sprocket, and there was enough slack that the chain lifted above the sprocket quite easily. Then I very slowly rotated the engine
by hand while observing the sprocket and chain. As I rotated the engine, the raised chain began to move slightly forward one link.
After the cam had rotated about 45 degrees, the chain began to lower into the correct socket. After more rotation,
the chain dropped into the correct position. I am sorry I should have taken pictures at the time. It is somewhat difficult to
visualize what I did. I imagine that there was quite a bit of strain on the components, but if it can jump on it's own without damage,
I felt confident that I could make it move one link without any problem with a very slow rotation.

Mike

 

Very ingenious solution, kudos on that one, get the physics of the chain and sprocket to do the work for you