my check engine code just came on, prior to that I had noticed a knocking sound when I start the car and the engine is still cold but it would go away after a couple of minutes, then recently on acceleration I started noticing a pinging sound audible enough in the drivers sit with the window open but it goes away when I ease of the gas pedal and on normal driving. I also noticed if hit 3500rm the engine hesitates a lil bit. I have always run it on the highest octane available in Massachusetts thus 93. anyone have knowledge on the causes of this, is it mechanical causing the obd2 code or is it electrical causing the pinging and hence the check engine light? what are the average repair costs?

 

check engine light came not code.