I went outside to get ready to go to my friends house, and when I start my car I hear this wear rattling/tapping coming from right near my cam gears. It sounds like valves ticking (They are a little bit, I do need an adjustment); and now my check engine light comes on. It's blinking 1 time, about every 2 seconds. I'm guessing o2 sensor, but not sure. Can anyone help?
jB

 

Once on a buddys motor the rocker cam loose.. and made massive noise.. i would check all valve terran... and the ecu code.. is it code 11 or 1 or 2 or 20... when ecu blink a blink that is long means 10
and a fast flash is 1