I have a 3ltr diesel xj that has an engine stumble at low speeds. Dealer has diagnosed turbo actuator lazy and not opening vanes properly on demand. Only started after last service and seems to have a bit more power since. I have read that if the actuator stick's open it will seem to have more power which can be catastrophic for the turbo and engine. Dealer has ordered me a new actuator but they are on back order, still not convinced it is the actuator that's causing the engine stumbling at low speeds. Has anyone come across the same problems.