Looks like my diverter valve went today. It wont let the car hold idle if i dip into boost at all, and makes a fluttering sound now instead of the normal "woosh". Where exactly is it located on a 1991 9000?
On our NA models the "hooter" valve is in plain sight on the turbo intake hose between the air filter and the turbo. The hoses run from the turbo outlet through the hooter to the turbo inlet allowing the blow off air to keep the turbo spinning. Ours are cheap looking black plastic and an easy DIY replacement.