Mitsubishi 3000GT Service Manual page 434

INTAKE AND EXHAUST - Intake Manifold Plenum <Turbo>
Throttle body
TSB Revision
INSTALLATION SERVICE POINT
Caution
If installed in an incorrect direction, idling failure or other
problems may occur.
INSPECTION
Check the following points; replace the part if a problem is
found.
INTAKE MANIFOLD PLENUM CHECK
(1) Check intake manifold plenum for defect or cracks. Re-
place if defective or cracked.
(2) Check load (negative pressure) of drain port. Clean if
required.