On certain passenger vehicles equipped with 3800 V6 (L36) engines and certain delphi fuel pressure regulators, the regulators have a much higher than usual rate of fuel leaks. A leak can allow fuel to enter the intake manifold through a vacuum line. If the engine does not start when cranked, the fuel from the leaking regulator and a mistimed spark can cause a backfire.
Dealers will install new fuel pressure regulators with improved diaphragms. The recall will be conducted in phased mailings. Phase 1 began on June 30, 2004, and phase 2 began on September 30, 2004. Owners should contact Buick at 1-866-608-8080, Oldsmobile at 1-800-630-6537, or Pontiac at 1-800-620-7668.