6000 V6-173 2.8L VIN W FI (1986)
Intake Air Plenum: All Technical Service Bulletins
Intake Plenum - Rough Idle, or Poor Engine Performance
Number 86-6(Gasoline)-22 Date
2/86
Subject:
INTAKE PLENUM RUNNERS RESTRICTED BY CASTING FLASH
1985-86 6000 AND FIREBIRD MODELS WITH 2.8L MPFI V-6 ENGINES RPO CODES LB6 & LB8, VIN CODES W & S
INTAKE PLENUM
A condition exists whereby one or more ports of the inlet plenum can be partially or completely blocked with casting flash. The condition can cause
rough idle, rough engine operation, and/or poor performance. The casting flash, if present, can be found approximately two (2) inches in from the
plenum mountingsurface by probing with feeler stock. The casting flash may not be visible to the eye (see figure 1).
