Engine - Misfire Under Hard Throttle
Bulletin 87-6E-18Date July '87
Ref. No. 87-154-6E
Corp. Ref. No. 736515
SUBJECT: ENGINE MISFIRE UNDER HARD THROTTLE (TURBO BOOST)
MODELS AFFECTED: 1987 2.0L LT3 (VIN CODE M) ENGINE
Some engines in subject vehicles may misfire under hard throttle, such as during turbo boost conditions. The miss is caused by excessively high ignition system demand voltage of the high gap (.060") spark plug and combustion conditions.
The misfire is repairable by installing a .035" gap spark plug, Part Number 5613820 (R42XLS, a 1986 turbo spark plug).
For future spark plug service on this vehicle, a page of peel-off labels is included with this bulletin (to dealers only). This reference label should be placed on the same mounting surface and near the current vehicle emission control information, "Tune-Up" label.
Use applicable labor operation.
SPARK PLUG GAP HAS BEEN CHANGED TO .035" PER CORP. BULLETIN I.D. 736515. FOR SERVICE REPLACEMENT USE PLUG TYPE R42XLS OR EQUIVALENT 10079640