Certain passenger vehicles equipped with 3800 V6 (L36) engines and certain Delphi fuel pressure regulators have a much higher than usual rate of fuel pressure regulator diaphragm leaks. A leak can allow fuel to enter the intake manifold through a vacuum line.

In low battery conditions, which can occur more often in these vehicles because of higher accessory loads, if the engine does not start when cranked, the fuel from the leaking regulator and a mistimed spark can cause a backfire. The backfire can rupture the intake manifold. The rupture of the intake manifold can displace a fuel line, pulling an injector out of place, and causing a fuel leak. If there is an ignition source, a fire can result.

Dealers will install new fuel pressure regulators with improved diaphragms. Owner notification is expected to begin during January 2004. Owners should contact Buick at 1-866-608-8080.