...ye check the alternator as it doesnt sound that it is in good condition...it is time consuming i know...iaw software is great tool when there is an sensor issue to discover it but if you say that the alternator is playing up sure check this also.......btw you can take out also injectors and get them checked or even you can do it yourself...there are some diy on you tube just to see if they are spraying..hope you sort it out