I'm literally all 'shook up'. For almost a year I've been trying to diagnose and fix our 1990 740 with Regina-Rex Fuel/Ignition. It cuts out, sputters, etc (but never dies) between idle and around 2500 rpm. The tach drops to an idle reading during these episodes and does not follow engine speed. Once an episode starts, it usually progresses to the 'limp home mode' of idle rpm (when accelerator depressed, cuts out). I've replaced: fuel pump relay, radio interference (injector)relay, fuel pressure regulator, rpm sensor, throttle switch, power stage, plugs, wires, distributor cap, etc with no results. Have cleaned throttle body, installed new intake hoses and checked all vacumn lines. All seem ok. Dealer has been unable to diagnose either. I've replaced the fuel module - no fix, and bought a new ignition module which will only run at idle and not above (I've waited too long to return it now, rats!!!). This is an intermittant problem that seems usually to be heat related (much worse on hot days). Also increased by use of A/C. Could it be a 'load signal' related problem?? The car normally (90% of time)runs great for first 10-20 minutes or about 20 miles. Fuel consumption is good (22-23 mpg). I can sometimes get engine to 'catch' by flooring accelerator, then it will run great above 2500 rpm. Have checked and all service bulletins appear to have been applied relative to Regina/Rex replacements. Engine will usually return to normal (if not progressed to limp mode) when gear shift is moved to neutral or park? Before I buy yet another Rex ignition module (seems to be the obvious problem?!) I'm hoping someone out there has had a similar problem. Help please. I'm at the end......