Hi, I was getting a problem of stalling when approaching junctions etc and like a fool started playing with the engine. I moved a screw right next to the throttle position sensor on the throttle body, it has a lock nut with an allen key grub screw in the middle of it. I now have my management light on and the car runs at 1500rpm on tickover and sounds like it is running on 3 cylinders, also it will only rev to 3500rpm which i assume means it is in limp mode. Any ideas on what to do without main dealer assistance.

Thanks in advance.