I have a slight knocking noise from the car when idling, I am thinking it is rod knock but not sure exactly. If i rev it a bit the noise will go away and it will sound fine and then after driving when i come to a stop light it will sometimes be present again. Does this sound like a spun bearing or something else?

 

ttt

 

Spun bearing. If you stop driving it NOW, you might be able to fix it with no ill effects.

 

more likely a main or rod bearing?

 

If it's a bearing it will be a rod.Forged pistons will make some noise.Has it always been good and the noise just started or it's a new build that did this from the start?

 

completely OEM B18b1, it started awhile ago and hasnt really caused any problems.