91' 940 Turbo stalls on going over driveway curb, but also at low RPMs (especially while turning/braking or coasting). I recently fiddled with the coil wires, then I got a 2-1-4 error code after check engine light came on. Problem worse now after the error code for rpm sensor (takes 4 tries to get out of the driveway). Have replaced ECU, fuel pump relay, cleaned conections, tried different air mass meter, new coolant temp sensor.
One odd thing is that I used to be able to predict when it would stall (that particular day) when the car first started as it sounded like it only had about half the power it should--like it was non-turbo (even wimpier sounding than my 740 B230F) Now it sounds that way all the time. It's become unsafe to drive it stalls so often now. I'd like to think that the loss of power/dramatically different sound of the engine might be a give-away to someone who may have run into this.

Ideas? Please!