2003 CHEVROLET MONTE CARLO User Comment / Complaint

I have a 2003 chevrolet monte carlo. beginning in august of 2006, my check engine light came on one day so i took the car to the dealer to have it checked. the diagnosis was an exhaust rocker stud had pulled out of the cylinder head. they heli coiled it ,and it was fine for a while. then in sept. 2006, the same thing happened again,this time the opposite cylinder head. this time they fixed 3 of the studs. now march 2007,the first cylinder head has the same problem. the dealer was unable to repair the head so it was replaced. while the car was there,the technician removed the cover from the opposite and found one rocker was loose again,so they removed that head and sent to a machine shop. i have an extended warranty on the car but still ended up paying close to $300 on my deductible and rental car. in seven months i have the same problem,there's got to be something wrong. is the some way i can get the manufacturer to do something? 8jb