Engine - Detonation at Cruising Speed (40-55MPH)
90pontiac07Subject: IDLE SHAKE/REVISED SERVICE PROM - CALIBRATION - 1982 6000 AND PHOENIX EQUIPPED WITH 2.5L EFI AND AUTOMATIC TRANSAXLE
A new PROM has recently been released with revised spark timing calculations and slightly increased idle speeds.
The change in spark timing was made to eliminate any detonation under moderate acceleration at cruising speeds (40-55 MPH). The increased idle speed will reduce vibration or shake at idle speeds.
The service part number for this new PROM is 1226169 (broadcast code 0262-AOS). This PROM is to only be used on 1982 Phoenix and 6000's with the 2.5L EFI, automatic transaxle, and first design (3-board) ECM. The second design (2-board) ECM has the spark revision already incorporated in its PROM.
PROM's should be replaced only as required to correct above conditions.
Number 82-I-195 Section 6 Date 07/82