For 1990-2009 cars

# POOR PERFORMANCE / POWER LOSS INJECTION PUMP TIMING

#### Vehicles Affected: Vehicles Equipped with 4.3 or 5.7l Diesel Engines

Anything that affects the fuel pressure to the injection pump, such as a plugged filter or pinched line, will change the timing. A restricted fuel return line will also cause a timing shift. If the pump timing is adjusted, and later it is discovered that the fuel system is restricted, the timing may be incorrect. Should this situation be encountered,,it will be necessary to check and adjust pump timing as necessary.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.