S15/T15 2WD Jimmy V6-262 4.3L VIN W CPI (1993)
Engine Control Module: All Technical Service Bulletins
Engine - Intermittent Hesitation/Low Power/Rough Running
File In Section: 6E - Engine Fuel & Emission
Bulletin No.: 67-65-37
Date: June, 1997
Subject:
Intermittent Hesitations, Low Power, and Rough Running Engine in Cold Temperatures (Replace PCM)
Models:
1993-95 Chevrolet and GMC, M/L, S/T Models
1993-94 Oldsmobile Bravada
with 4.3L Engine (VIN W - RPO L35) and HYDRA-MATIC M30 Automatic Transmission only
Condition
Some owners may comment about intermittent hesitations at ambient temperatures below -10°C (14°F). The hesitations may also be associated with low
power or a rough running engine. This condition may lead to a closed throttle stall when stopped. This condition, if encountered, would most likely occur
within the first few minutes of engine operation after a cold overnight soak. If the low power condition were encountered, the engine would run normally
after one vehicle ignition cycle (Off/Start/Run).
Cause
Under certain conditions a high frequency transient voltage spike back feeds into the engine controller (PCM) and causes it to reset. PCM resets would
manifest themselves as a bump or hesitation. Infrequently these resets lead to an incorrect fuel/spark run mode which is associated with the low power
condition.
Correction
Replace the PCM with a new PCM. Choose the appropriate PCM from the list below.
Year
Model
PCM Part
1993
M/L and S/T
16245357
1994-95
M/L and S/T
16245358
