Is it ok to run a tank of Supreme gas thru my 2001 Buick Park Avenue 3.8

Yes,you can. You can run it all the time if you want to,just cost more. If you have the 3800 V6 engine (VIN Code K), use regular unleaded gasoline rated at *87 octane or higher*. If you have the 3800 Supercharged V6 engine (VIN Code 1), use premium unleaded gasoline rated at *91 octane or higher*.