the other day I was at home depot and they had a demo display of a tool I think it was made by stanley but it had about a3 in. tv screen it was hand held with about a3 ft. flexible probe with a light and tiny tv camera and i remember thinking it would go into a spark plug hole you might check it out I think it was about $ 149.95 but I think it would work for alot of stuff might be good for piece of mind.....ted