Engine - High RPM Upon Initial Shift Into Drive Gear
88pontiac06Bulletin Number: 88-6-37
Reference Number: 836510R
Publish Date: 4/88
Subject: HIGH IDLE ON INITIAL SHIFT INTO DRIVE GEAR
Models
Affected: 1987 AND EARLY 1988 MODELS; SUNBIRD MODELS 2.0L/VIN K AND FIERO MODELS WITH 2.5L/VIN R
Customer comments of a higher than normal engine idle RPM upon initial drive gear engagement that decreases within a few seconds, may be because of an ECM software condition.. This drive only RPM condition is similar to a "carbureted fast idle" or "high cam step" level.
The above condition may be brought on by repeated engine "revving" in park/neutral or by a rolling/stopping action while in neutral. This condition will only occur in a non A/C vehicle or with A/C off.
The following ECM calibration PROMs will help overcome the above condition:
In conjunction with this type of comment, stored diagnostic codes should be looked at as well as the symptom section of the Service Manual.
Use applicable labor operation and time.
* The suspect ECM part number can be checked by using a Tech 1 scanner.