1992 Dakota sets code 27 when outside temperature is below 45F. The code does not set above 45F. When below 45F, code 27 sets most times especially during cold morning starts. Sometimes the truck will start without setting the code below 45F, but then it will eventually set or it will set and then go away - the check engine light is still on, but the truck will run much smoother - I will turn the truck off and then on and the check engine light will stay off - temporarily. Once set, the truck runs rough. Code 27 is a fault with the #5 injector drive circuit. My mechanic says I need a new ECM. It seems my issue is temperature related - could it be my ECM or a temp sensor? I would hate to change the ECM if I don't need to.