Engine - Miss/Stumble/Rough Idle
Article No.94-2-7
01/26/94
^ IDLE - ROUGH - TOWN CARS BUILT FROM 8/1/90 THROUGH 11/30/92 AND GRAND MARQUIS/CROWN VICTORIA VEHICLES BUILT FROM 1/1/91 THROUGH 12/31/91
^ IGNITION SYSTEM - INTERMITTENT MISS, STUMBLE, ROUGH IDLE - TOWN CARS BUILT FROM 8/1/90 THROUGH 11/30/92 AND GRAND MARQUIS/CROWN VICTORIA VEHICLES BUILT FROM 1/1/91 THROUGH 12/31/91
^ MISS - INTERMITTENT - TOWN CARS BUILT FROM 8/1/90 THROUGH 11/30/92 AND GRAND MARQUIS/CROWN VICTORIA VEHICLES BUILT FROM 1/1/91 THROUGH 12/31/91
^ STUMBLE - TOWN CARS BUILT FROM 8/1/90 THROUGH 11/30/92 AND GRAND MARQUIS/CROWN VICTORIA VEHICLES BUILT FROM 1/1/91 THROUGH 12/31/91
FORD:
1992 CROWN VICTORIA
LINCOLN-MERCURY:
1991-92 TOWN CAR
1992 GRAND MARQUIS
ISSUE:
Intermittent miss, stumble or poor idle quality when engine speed is less than 1000 RPM may be due to inadequate fuel distribution.
ACTION:
Confirm that ignition system connections are properly installed and perform normal diagnostics to be sure no other fault is present. If a misfire fault is found and all components check OK, replace the Ignition Control Module (ICM) with a new improved part. The new ICM has a repetitive spark calibration. This feature allows the spark plugs to fire multiple times when engine speed is under 1000 RPM, resulting in improved idle quality. Refer to the following procedure and to the Service Manual, Section 03-07, for service details.
NOTE:
PERFORMANCE OF THIS PROCEDURE REQUIRES THE USE OF THE SERVICE BAY DIAGNOSTIC SYSTEM CART (SBDS) FOR BEST RESULTS.
1. Verify concern by performing an SBDS Power Balance Test with the vehicle idling in Drive.
NOTE:
IF SBDS IS NOT AVAILABLE, VERIFY THERE ARE NO SPARK PLUG OR SPARK PLUG WIRE FAILURES BY USING A NEON BULB SPARK TESTER OR AN AIR-GAP SPARK TESTER.
2. Observe the test for ten (10) minutes to determine which cylinder(s) are "missing". Refer to Figure 1 for a typical pattern of a cylinder misfire.
3. Verify that all spark plugs and spark plug wires are functioning properly; replace as required.
4. After confirming that there are no component failures, replace the ICM with an improved part (F2PZ-12K072-A).
PART NUMBER PART NAME CLASS
F2PZ-12K072-A Ignition Control Module (ICM) A
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS:
Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage And Eligible Under Emissions Warranty Coverage
OPERATION DESCRIPTION TIME
940207A Remove And Replace The 0.3 Hr.
Ignition Control Module
DEALER CODING
BASIC PART NO. CONDITION CODE
12K072 08
OASIS CODES:
608000, 608400, 609000, 609400, 611000, 611500