Do you hear a strange chirping at idle and during acceleration? On the dashboard start lighting TCS and the Check Engine (P0401)? It’s high time to check the EGR valve.
I will share with you the solution of the problem that I encountered with keyboard Roland E-20. I know that this is not an isolated case. E-20 is rather aged… manufactured in 1988, but because it has a soul, I decided not to give up and attempt resuscitation 🙂