If your 458 is setting a P0492 code, its a quick fix. Often the valve gets stuck shut from sitting. The engine fires up and makes about 15 hg of vacuum and thats not enough to unstick it sometimes. So remove the side engine cover panel and slip the hose off the valve (see photo). On mine I pumped my vacuum up to 18 hg and it released. If it still doesnt release, keep the vacuum on it and lightly rap on the base of it where it bolts on the exhaust and it should pop open. Clear your code and drive it and your Permanent code should clear. Image Unavailable, Please Login
