Is it possible to have engine damage and have no CEL? I'm having what sounds like a rod knock to me but not sure as it's driving me nuts. Seems to be fine at idle but sound rough when I get above 1500K RPMS.. Any thoughts are appreciated.

Thanks, Joe

 

Its engine piston and nossels have to repair and proper tuning done on it.Engine oil should also change with it so after the whole process it may increase you expectations and noise from the engine issue solve.