Honda 2012 insight hybrid intermittent limp mode fault

[SickofmyHondaInsight]

Hi looking for info/help regarding my mums car. Car shudders, slows down to limp mode, (walking pace), difficulty crawling up slight slope when in Limp mode . Need to turn engine off for few minutes to enable her to crawl up slope. Lights showing on dash are engine fault, circular fault and traction control. she has replaced all 8 plugs on 2 occasions over 2year period and just had the injector replaced. AA attended 2 occasions said 2nd plug not firing, they clean it to get car to go. I have taken to mechanic who serviced the car. few weeks later same problem, mechanic advised it was possibly the injector that he replaced a few weeks ago. Same issue happed today, shuddering, crawl speed. AA called out on 2 occasions saying 2nd plug not firing, they clean it and the above problem happens again. as you may have noticed has anyone had a similar problem/ experience that Can advise please. as to what we can do regards a fix to the issue