Hi all, my NA 850 misses intermittently sometimes on light throttle, sometimes heavy throttle (but will sometimes clear itself on backing of, off course other times will go right on missing). I thought it would be my fuel filter ( due replacement especially after running with a low fuel level last week). I have scoured various posts here at the BB and other forums as well. WOW, it seems a lot of people with a similar problem, yet no one finger pointed at a particular cause . A lot of opinions expressed relate to turbo models only, yet the problem seems to be a common issue. Klaus mentions the O2 sensor a bit. Is there a test i can do for this? I dont have access to a code reader or any fancy equipment. Is there a logical sequence of checks and cleaning of parts to follow to isolate my problem? Also could the knock sensor cause an issue such as this? I realise this is a light post compared to some others, but i need to start somewhere and with a basic check list. Thanks for listening. David