High alt performance problem

[reflected]

I've been trying to figure out the secrets of full CEM and it's very frustrating, but exciting at the same time.

Now I think I got the hang of it, but there's something I can't understand. I can fly the 109 OK, my question is about Merlin engines.

So I manage the radiator to keep the temps below 120 C. I also reduce the RPM when I can, I fight at 2850, and only use 3000 RPM for very short times. I understand this is the only way to keep your oil temp low, isn't it?
I mean it's always at 95C, very hard to cool down.

At lower altitudes I do fine, however, when I go up to 14,000 feet or above, I can't seem to keep it low (oil). Up there I should be using 3,000 RPM according to the pilots notes, but it seems that I have to reduce the RPM to 2,300 otherwise my oil temp would go through the roof. With 3,000 RPM my engine dies almost immediately. Why is that?

Also, the mixture should be automatic, but up there I start losing power rather quickly. Maybe these two problems are related? Is there something I'm missing?

Thanks

PS: all this with head shake off, because if I turn it on my whole plane vibrates like crazy no matter what I do up there.