cutting out

RE-SEAT every electrical connector you can see.
Re-Seat that is remove and place back in EVERY Fuse in your Fuse Box.
Re-Seat every Relay….

Why? because you are cleaning the connections.

Here is a Fuse holder that I failed to clean in the 10 years of Ownership, well now that it has been replaced (the socket) and I installed a 30 amp Breaker, I shouldn't see that issue….. On a side note, I replaced the same fuse on my other car, and installed a breaker there as well….





Remove and Replace the Connections on the Coil as well.

Gremlins, weren't a AMC issue, they attack with a cunning eye to intermittent operation.
If you have a Carb'ed car and funny things happening under load, then you usually have an electrical issue.

You can Relay your Headlights, and Radiator Fan,,,,,
You can Relay your Starter as well (heat soak).

Cabby-info.com has all the CIS grounds and there is a link in my DIY's for Digifant…..(with Pictures).

I just helped a fellow, and it was the Coil connections being dirty that caused his intermittent stumble.

try the lights and blower individually, see if its one or the other thats causing the drop or if its both together.

the main fusebox earth goes to the 4 way white spade block hanging off the end of the fat brown from the battery in your headlight loom. it'll have a few other earths on there, basically if its quite thick and has a black or brown spade housing then it should go to the white spade block. out the back of the block is another thick brown that needs to go to the earth claw above the fusebox.

include all of these plus the spades on your claws in your unplug and replug mission

I've cleaned up the chassis to gearbox earth, fault remains. Im wondering now if this issue may also be related to the car getting up to temp, as when its cold it will move ok but when up to temp needs revs to keep it going and will still cut out.

Thanks again both for your detailed help, I will continue to work through your suggestions

If it runs okay cold but plays up when warm it might be worth checking the choke is opening fully, have a look at the plugs when the problem occurs.

ok next step remove the brush pack/volt reg from the back of the alternator and check the condition of the brushes. also buff up the electrical contact points between it and the alternator:

Plenty to be getting on with.
6v is low at your coil, if you have the resistance wire intact you should be getting about 9v when running, a bit more with with the engine cranking, and the coil should be a 9v, not a 12v.

Thanks everyone for the help, I will continue to work through all the suggestions and see how I get on

Okay done some more fault finding today

1. Every fuse replaced with new ones
2. Coil connections replaced
3. side lights cause no drop, headlights cause more of a drop than the fan
4. Connections at earth claw re-seated
5. Nothing on the alt to remove, only a small plastic block with wire connection
6. Coil is 9v when the engine isn't running, its the wire to the coil which are 12v
7. Cleaned up the alt to starter and starter to battery ends

Fault remains, still getting a voltage drop

pics of the alt? you should be able to repalce the brush pack usually

I think I'm right in this - edited version - with the ignition on you should get 9V  at the coil, with the engine running it will be the same, about 9V, and with the engine cranking somewhere  between 9V and 12V.
This is  if you are still running with the ballast wire, if it's been by-passed and a 12V coil fitted it won't be so.
Whether the low voltage is your problem I don't know, I've got an old bike with two 12V coils, with electronic ignition fitted they're in series and only get 6V each, it runs okay.

on ignition and when running you will see reduced voltage at the coil on points ignition, because of the resistance wire from the fusebox.

when cranking you should see around 12v becasue there is a wire from the coil to the starter, this is there to boost the volts while its cranking