I have a Brabus 3.6 1989 Coupe.
My Brabus
What sort of mileage has the car got on it?
Mine is a 100k example and it idles at 750 rpm, with the oil pressure between 1.5 and 2.
Where abouts are you based? I've had some work done on mine by George Fraser in Wembley, London. There's a chap there that know the Brbaus inside out.
There is a sensor on them which is notorious for playing up which can give similar problems to yours. I will try and find out which one it is.
Just out of curiousity how much did the head gasket cost? Are the rumours of £500 for just the gasket true??