rarocena

Hi, I have a problem with my european 350sl from 1978. The car cold starts ok, reving up normally to aprox 1300 rpm.But if you press the throttle, it gets to a max of 3000 rpm and starts to vibrate.Its not possible to get more than 3000 rpm. Also after a few minutes, when it gets warm, it does not idle correctly and finally stops. If you keep it reved, it does not stop, but you can not get more than 3000 rpm.
The car has Bosch k jetronic fuel injection.
I checked fuel pump relay and it seems ok.
Any suggestions where to continue would be much appreciated.