The coolant temperature sensor needs to be working - it's a cheap part so worth replacing. There's also an auxiliary injector for cold starts and that will be triggered by the temperature sensor (via the injection control module).

If the car works well hot, then it sounds to me as if the mixture is not rich enough when cold. Either the system knows it's cold and is not able to inject more fuel or the system thinks it's not cold. Again, aux injector or temperature sensor.

I haven't had to think much about your symptoms because all problems I've had (exactly the same system) have been the reverse - fine cold starts, problems when hot.

All I can recommend with confidence is that you start with cheap parts if you're in doubt. There's only one temperature sensor and it's cheap. Oh, I've just forgotten the air intake sensor that we have in our systems and it's attached to the side of the air filter housing. You need to unplug it to remove the air filter housing so you can't miss it. Again, it's a €20 part so easily replaced.

It's also worth making sure that fuel filter is in a good state - although, for me, a bad filter affected hot running more.

Your MAF is not on the side of the fuel distributor, the fuel distributor in mounted above it! (unless I misunderstand). I think you are referring to the so-called governor (or EHA) which is a fine tuning device associated with the basic, electronic side of the KE-Jetronic system. I don't think that's the root of your problem. Your MAF is the hinged plate in the air intake, just under the air filter.

Your duty cycle suggests very rich mixture. Have you tried adjusting it to 50% (fluctuating)? Are you able to adjust it? What does it read Ignition On/Engine Off? Does your MAF move smoothly down when you press carefully down on the plate?

Don't throw money at the problem until you are 100% sure there's a faulty, costly part. The system is tried, trusted and very reliable, assuming it's maintained well with.

Keep calm, keep at it and report progress.

RayH