[HarryD]

There is an old saying, there are three types of CIS owners:

1) The guys with working CIS systems are probably out driving their cars so they won't reply.
2) The guys that tinker with their CIS systems and have them royally screwed up will keep you running in circles with suggestions.
3) The guys that have spent a fortune on Webers or EFI will tell you they're great to justify their expenditure to themselves.

That said, before you tinker with the CIS components, make sure the car is in excellent tune.

Verify the points (if you have them), plugs, cap, rotor, wires, fuel filter are in tip top shape. Replace if there is doubt.

Drain any old fuel and refill with fresh (non ethanol if possible) fuel.

Do a valve adjust.

Set timing and dwell (if you have points) to spec.

Once this is done, and the car is still not running well, look for vacuum leaks and correct as needed.

Once these items are resolved, it is time to look at the CIS parts. Lots of threads on troubleshooting.

The good news is that once you have your CIS dialed in, it tends to stay that way.