A bad DISA valve can cause a variety of issues, from a loud racket in the engine bay, hesitation at low rpm, and a rough idle with lean codes.
If the valve is making a loud noise, we recommend replacing it as soon as possible. It is possible for the pin holding the flap to be sucked into the motor causing serious damage.
Very easy to replace, just need to undo the 4 bolts holding it to the intake manifold.
