Some customers may comment on poor engine performance and the check engine light being illuminated on 2001-2003 GM 4.3L, 5.0L or 5.7L engines (VINs W, X, M, R – RPOs L35, LU3, L30, L31). Upon further investigation, the technician/installer may find DTC P0300 code.
This condition may be due to high levels of internal corrosion in the distributor, causing misfire, rough idle, stall and non-running condition. The corrosion is attributed to a lack of airflow internal to the cap caused by the vent screens being clogged with debris.
To correct this condition, remove the vent screens and inspect the internal components of the Distributor Ignition System using the procedure listed below. If the distributor base has to be replaced, the vent screens will also have to be removed on the new distributor. If there is evidence of this internal corrosion, replace the affected component.
1) Inspect the distributor cap. You may notice a white residue on the cap walls. For higher mileage occurrences, the interior of the cap may have changed to medium brown in color
2) Inspect the distributor rotor. You may notice the presence of black streaks on the plastic surface. More typical evidence would be visible green spots on the copper surface of the rotor segment.
3) Inspect the distributor base. You may notice high levels of surface rust on the distributor shaft or surface contamination on the sensor hold down screws.
4) Inspect the distributor vent screens (1). If the vent screens are present, remove them by using a plastic-handled, long blade awl or pick (2). Insert into the airflow vent screens and pop them out. Refer to the figure for removal procedure. If the vent screens have been removed from the base of the distributor, then check the airflow inlets for being clogged with debris.
Part Number Description
10452458 Cap, Distributor (V6)
10452457 Rotor, Distributor (V6 and V8)
93441559 Distributor (V6)
10452459 Cap, Distributor (V8)
93441558 Distributor (V8)
Parts are currently available from GMSPO.
Some or all of the preceding technical information was provided by the
Automotive Parts Remanufacturers Association (APRA). For more
information on technical bulletins available through APRA call
703-968-2772 or visit www.AutoBulletins.com.