I am not so sure about the injectors. Your Comm port moves around a bit when it shouldnt. Not sure if you have it in a tight place or its been yanked on once or twice.

I would also check your comm cable for internal shorts as well.

if the injector was the problem then you would see damaged fets that are mounted to the case or an issue with the flyback board. I have seen shorted injectors cause the flyback to fail altogether and the end result is an injector circuit stuck wide open.

Terry