It could be a psychological problem (see the movie Zoolander, where Derek can't turn left).
Seriously, I don't know of any specific problem where only a right turn will cause a stall - there's probably some other problem where the turn is just coincidence, and I agree, I wouldn't start at the control module. I would go through the basics: plugs, vacuum lines, wiring etc an dtehn look for an independednt for further diagnosis.