I have not had the problem you are having so I don't know what to tell you but I will look around and see if I can find out anything.
How long have you had your car?
There are other places you can ask too I attached the links if you don't know about these sites.
If I find anything I'll let you know.

Grand Prixs Of North America • Index page
Club Grand Prix! Your online Grand Prix & G8 resource
got3800.com/forum/index.php