+1 fuel system.
Since you said that you car idles fine but the problem appears at 70km, I would lean toward the fuel system. What is the fuel pressure at idle and at 2500 rpm. Check the fuel pressure, this validates the fuel pump and pressure regulator. Sonic cleaning the injectors ensures they produce the proper spray pattern all the way through redline. You should also check the coil's and plug wire resitance. Bad lead would register as open, have huge variances in impedance or would have electrical arc you can see at night. The E30 motronic system is self adjusting. Therefore, things such as idle speed, ignition timing, fuel injector spray duration, etc are all controlled by the ECU. Check the condition of the cap and rigor. It they are severely pitted or have carbon tracks, clean or replace them.
Big Boyz with Bad Toyz
Big Boyz with Bad Toyz.
Last edited by BigBoy740il; 12-01-2012 at 08:03 PM.