Mustang V8-302 5.0L CFI HO (1985)
Technical Service Bulletin # 91257
Date: 911213
Engine - Hard Cold Starts/Hesitation/Stalls On Start-Up
Article No.
91-25-7
12/13/91
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HARD COLD START - DURING INITIAL START-UP, IDLE OR DECEL - EFI ENGINES - SLUDGE IN THROTTLE BODY AND/OR
IDLE AIR BY-PASS VALVE
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HESITATION/STALLS - DURING INITIAL START-UP, IDLE OR DECEL - EFI ENGINES - SLUDGE IN THROTTLE BODY
AND/OR IDLE AIR BY-PASS VALVE
FORD:
1983-87 EXP
1983-91 ESCORT
1984-90 MUSTANG, THUNDERBIRD
1986-90 TAURUS
1986-91 CROWN VICTORIA
1988-90 TEMPO
LINCOLN-MERCURY:
1983-85 LN7
1983-87 LYNX
1984-88 CAPRI
1984-90 COUGAR
1986-90 CONTINENTAL, MARK VII, SABLE
1986-91 GRAND MARQUIS, TOWN CAR
1988-90 TOPAZ
1991 TRACER
LIGHT TRUCK:
1985-90 BRONCO II, BRONCO
1985-91 ECONOLINE, F-150-350 SERIES
1985-92 RANGER
1986-91 AEROSTAR
1991 EXPLORER
ISSUE:
Hard cold starts, hesitation and stalls on initial start-up or during idle or decel may be caused by sludge in the throttle body and/or idle
by-pass valve. Sludge deposits or oil film on the throttle body bore and plate or the idle air by-pass valve may cause one or more of the
following conditions.
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Hard Cold Start
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Stall On Initial Start-Up
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Stall During Idle
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Stall During Decel
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Rough Idle
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Rolling Idle
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Hesitation During Acceleration
ACTION:
A new idle air by-pass service kit (F2PZ-9F939-A) is now available for service use to correct sludge contamination concerns of the throttle
bore and plate only. It eliminates the need to clean the majority of past model throttle body applications. Cleaning is not required on sludge
tolerant throttle body designs released for 1991 and newer model years.
