complete shot in the dark, but from experience, a friend had a very similar experience and we tried all kinda stuff, air leaks n air flow meters ect, and ended up being his alternator :shock: cant state why as i dont know, but changed it and all trundling along ok, i did remember that his old alternater was/appeared to be producing voltage ok, not sure about amps though, thought i would pass the info on anyhow, good luck