Another timing problem
 

Still playing with timing. Today, I'm getting erratic timing on #1 - the mark bounces around at idle. So, as a test of the gun, I connected to another plug wire. Steady as a rock. So, I set the timing by #4 at TDC. Steady as a rock. Go back to #1 and it still bounces.

So, I think the gun is fine. Is this a plug wire problem? Cap? Rotor? Dizzy? Any of the above? Being a software geek, I'm looking for debug ideas - where to start....

Check spark plug by swaping them. Same goes with wire-swap as well.