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1995 Bronco XL 5.0L
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Week ago truck (95 XL 5.0)started doing this, got it to shop by left foot brake/right foot accelerator at stoplights. Shop tried for 3 days to get it to replicate and couldn’t (good mechanic, they’ve done good work for me before). No codes or lights. They checked for vacuum leaks too. Picked it up, no issues for 24 hours and then started again. Sometimes when it does it it’s hard to get started again.
Not real mechanically inclined, slowly learning, but need to point the shop in the right direction. Found post by miesk5 below, is this the right starting point? Talked to a cop friend who drove a Bronco from this time on duty and said they had to have a shop clean the throttle plate every couple of months for the same situation? Need some help

yo,
Go thru all of this;
Idle Air Control (IAC) Sludge; Poor Idle TSB 91-25-07 for 85-92 Bronco & F Series & many others; "...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. Hard Cold Start, Stall On Initial Start-Up, Stall During Idle, Stall During Decel, Rough Idle, Rolling Idle, Hesitation During Acceleration. 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..."
Source: by Ford via Steve83 (Steve, That dirty old truck) at 1983 Ford Bronco TSBs & FSAs (Recalls) for '83-96 Broncos & F150s picture | SuperMotors.net

SM is still off a bit and you need to refesh page to see images; and I'll post info here for posterity in case.... because ProjectBronco.com was attacked recently and lost their Home Page and much more.
as Blue wrote; "...My anti virus just said the site has multiple threats!!!..."



TSB 91-25-07 IAC Sludge; Poor Idle

Publication Date: DECEMBER 13, 1991

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.
Hard Cold Start
Stall On Initial Start-Up
Stall During Idle
Stall During Decel
Rough Idle
Rolling Idle
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.

Install an idle air by-pass service kit (F2PZ-9F939-A) as applicable to provide a permanent correction for symptoms caused by throttle body sludge deposits. Refer to the instruction sheet included in the kit for installation details. Refer to Figure 1 for a specific application list of EFI (port fuel Injection) engines involved in this TSB article.

The idle air by-pass service kit (F2PZ-9F939-A) includes the following items.

One (1) Idle Adjust Spacer
Two (2) Gaskets
Two (2) Attaching Bolts
One (1) "Attention" Sticker
One (1) Instruction Sheet
Refer to the figure for the kit's components.
NOTE: EFFECTIVE WITH THIS TSB, THROTTLE BODY CLEANING IS NO LONGER COVERED UNDER 5/50 EMISSIONS WARRANTY, UNLESS AS SPECIFIED IN THE FOLLOWING APPLICATION CHARTS. FAILURE TO FOLLOW THE CORRECT PROCEDURE MAY RESULT IN THE CLAIM BEING DISALLOWED.
The idle air adjust spacer incorporates sludge tolerant design features that eliminate throttle body sludge related conditions. Once installed, throttle body cleaning is not allowed and periodic adjustment of the throttle body is not required.

CHECKS TO MAKE PRIOR TO SERVICE KIT INSTALLATION
Confirm that the following items are not causing the idle quality concern before proceeding with the service kit installation.

Contamination within the idle air by-pass solenoid
Lack of fuel system control (excessively rich or lean)
Ignition timing change
Incorrect or malfunctioning EGR system
Incorrect or malfunctioning cooling system
Vacuum leaks (air intake manifold, vacuum hoses, vacuum reservoirs, power brake booster where applicable).
EEC diagnostics have been performed and vehicle malfunction indicated service output codes have been resolved and cleared.
If any of the areas listed above are found to be at fault, correct them before proceeding with the service kit installation.

IDLE SPEED ADJUSTMENT
WARNING: BEFORE PROCEEDING WITH THE IDLE SPEED ADJUSTMENT, VERIFY THAT THE FOLLOWING ITEMS ARE TAKEN CARE OF PROPERLY.
The transmission is in PARK or Neutral.
The parking brake is applied.
The wheels are properly blocked.
The engine is at operating temperature.
The heater. A/C, cooling fan and other accessories are OFF.
The EFI throttle body idle speed adjustment procedures for the various model year passenger cars and light trucks are outlined in step-by-step procedures. Select the appropriate procedure for the vehicle involved and adjust the throttle body idle RPM accordingly, after service kit installation.

THROTTLE BODY AND IDLE AIR BY-PASS SOLENOID SERVICE PROCEDURE
Detailed application charts for throttle body and idle air by-pass solenoid service procedures by engine VIN #/engine displacement/vehicle application and model year are shown. Refer to these charts to see if the service kit is to be installed and which service cleaning procedure, if any, is to be used.

SERVICE CLEANING PROCEDURES
The following items should be noted prior to beginning the service cleaning procedure.

Confirm that the correct service cleaning procedure is identified in the Application Charts, Figures 6-11, for the vehicle/engine combination being serviced.
Do not clean throttle bodies identified to accept service kit (F2PZ-9F939-A), IDLE AIR ADJUST SPACER.
Use a 1" (25.4mm) to 1 1/2" (38.1mm) wire stemmed horse hair or nylon bottle cleaner type brush.
Use rubber gloves and eye protection.
Do not clean throttle bodies identified with a yellow/black "ATTENTION" label.
Do not clean "Black" plastic air by-pass valves. Refer to TSB 89-13-8 for service details.
Do not run vehicles with air flow meters when the air duct is removed.
Do not use carburetor cleaner as a cleaning solvent. Use Carburetor Tune-up Cleaner (D9AZ-19579-AA).

PROCEDURE #1
THROTTLE BODY AND IDLE AIR BY-PASS VALVE CLEANING
CAUTION: DO NOT RUN VEHICLES EQUIPPED WITH AIR FLOW METERS DURING THE CLEANING PROCEDURE. IF THERE IS A YELLOW/BLACK "ATTENTION" LABEL ON THE THROTTLE BODY ADVISING NOT TO CLEAN, OR IF THE VEHICLE IS IDENTIFIED AS ACCEPTING SERVICE KIT (F2PZ-9F939-A), USE PROCEDURE #2 FOR IDLE AIR BY-PASS VALVE CLEANING ONLY.
Plug the actuator into the connector in the Rotunda Cleaner/Tester, Tool 113-00009.
Remove the air duct to the throttle body inlet.
Disconnect the idle air by-pass valve signal lead.
Attach the actuator harness plug to the idle air by-pass valve.
Start the actuator and then start the engine. Do not start engines that have air flow meters.
Spray just enough Carburetor Tune-up Cleaner (D9AZ-19579-AA) into the throttle bore to wet the bore and throttle plate.
Spray the Carburetor Tune-up Cleaner for about five (5) seconds into the idle air by-pass valve inlet passage while the actuator is operating.
Stop the engine and actuator. Let everything soak for fifteen (15) minutes.
After a fifteen (15) minute soak, saturate the cleaning brush with solvent and scrub between the throttle body bore and plate while holding the throttle wide open.
NOTE: IT IS NECESSARY TO APPLY SOME PRESSURE ON THE BRUSH WHILE SCRUBBING.
Repeat saturating the brush and scrubbing for one (1) to two (2) minutes, making sure to reach into the corners where the throttle shaft meets the bore wall.
Start the actuator and the start the engine. Do not start engines that have air flow meters.
Spray Carburetor Tune-up Cleaner into the throttle bore for up to one (1) minute to wash away residue. Do not spray for longer than six (6) continuous seconds on engines that have air flow meters and are not running.
Spray Carburetor Tune-up Cleaner into the idle by-pass valve passage leading to the inlet of the valve for up to one (1) minute. Do not spray for longer than six (6) continuous seconds on engines that have air flow meters and are not running.
Stop actuator and stop engine, if running.
NOTE: MAKE SURE THE THROTTLE PLATES OPERATE FREELY AND CLOSE PROPERLY.
Reinstall the air duct.
Start and run the engine for about one (1) minute to dry out the solvent residue.
Operate the actuator to make sure the solvent is purged from the idle by-pass valve.
Disconnect the actuator from the idle air by-pass valve.
Reattach the control signal lead to the air by-pass valve.
Check engine for normal operation. It may be necessary to reset the idle speed due to a previous adjustment for an idle concern. (Refer to the respective Powertrain/Emissions Diagnosis Service Manual, Throttle Body Section, for idle speed adjust procedure.)

PROCEDURE #2
IDLE AIR BY-PASS VALVE CLEANING ONLY
CAUTION: THIS CLEANING PROCEDURE MAY BE USED WITH SLUDGE TOLERANT THROTTLE BODIES WHICH ARE IDENTIFIED WITH A YELLOW/BLACK "ATTENTION" LABEL AND THOSE USING SERVICE KIT (F2PZ-9F939-A). NO ATTEMPT SHOULD BE MADE TO CLEAN THROTTLE BODY BORE/PLATE AREA BY DIRECT SPRAYING OR SCRUBBING. DO NOT RUN VEHICLES WITH AIR FLOW METERS DURING CLEANING PROCEDURE.
Plug the actuator into the connector in the Rotunda Air By-Pass Valve Adapter 113-00009, or equivalent.
Remove the air duct to the throttle body inlet.
Disconnect the idle air by-pass valve signal lead.
Attach the actuator harness plug to the idle air by-pass valve.
Start the actuator and then start the engine.
NOTE: DO NOT START ENGINES THAT HAVE AIR FLOW METERS.
Spray the Carburetor Tune-up Cleaner for about five (5) seconds into the idle air by-pass valve inlet passage while the actuator is operating.
CAUTION: AVOID DIRECT SPRAYING ON THROTTLE PLATE/BORE AREA
Stop the engine and actuator. Let everything soak for fifteen (15) minutes.
Start the actuator and the start the engine.
CAUTION: DO NOT START ENGINES THAT HAVE AIR FLOW METERS.
Spray Carburetor Tune-up Cleaner into the throttle bore for up to one (1) minute.
CAUTION: DO NOT SPRAY FOR LONGER THAN SIX (6) CONTINUOUS SECONDS ON ENGINES THAT HAVE AIR FLOW METERS AND ARE NOT RUNNING.
Stop actuator and stop engine if running.
Reinstall the air duct.
Start and run the engine for about one (1) minute to dry out the solvent residue.
Operate the actuator to make sure the solvent is purged from the idle by-pass valve.
Disconnect the actuator from the idle air by-pass valve.
Reattach the control signal lead to the air by-pass valve.
Check engine for normal operation.
NOTE: IT SHOULD NOT BE NECESSARY TO RESET THE IDLE SPEED SINCE ONLY THE IDLE AIR BY-PASS VALVE WAS SERVICED IN THIS PROCEDURE

WARRANTY COVERAGE
Throttle bodies and idle air by-pass valves on all EFI (Port Fuel Injection) engines through the 1992 model year that can be cleaned (as identified in the application charts) are covered under 5/50 Emissions Warranty Coverage.

For those throttle bodies identified as having sludge tolerant designs or using service kit (F2PZ-9F939-A) where cleaning is not allowed per the application charts, the warranty claims for cleaning will not be reimbursed even within the 12/12 warranty coverage period. Cleaning is not allowed. Service kit installation (single time) is covered under 5/50 emission warranty.

LABOR STANDARDS OPERATIONS
The labor operations shown in the following Operation/Description/Time columns are identified by procedure number and vehicle line. Specific engines for various vehicles are identified in the sludge cleaning procedure application charts. The throttle body cleaning operations with combinations and the air by-pass valve cleaning combinations will appear in future Labor Manuals under the following operation numbers.

9926 B - Throttle body and idle air by-pass valve cleaning
9926 B2 - Adjust idle speed
9715 A - Air by-pass valve cleaning only
9715 A1 - Adjust idle speed

PART NUMBER PART NAME
F2PZ-9F939-A Idle Air By-pass Service Kit
D9AZ-19579-AA Carburetor Tune-Up Cleaner

OTHER APPLICABLE ARTICLES: 89-13-8
SUPERSEDES: 88-24-5, 88-24-6, 89-16-5, 91-10-9, 91-7-4
WARRANTY STATUS: Eligible Under Warranty Coverage As Stated In The Text Of This Article

OPERATION DESCRIPTION TIME
912507A Idle Air By-Pass Valve Cleaning - 1983-85 Escort, EXP, LN7, LYNX 1.6L EFI. 0.5 Hr.
912507B Idle Air By-Pass Valve Cleaning - 1986-91 Escort 1.9L EFI, 1986/87 EXP, Lynx 1.9L EFI, 1991 Tracer 1.9L EFI. 0.5 Hr.
912507C Idle Air By Pass Valve Cleaning - 1984-87 Mustang 2.3L T/C, 1986/87 Capri, Cougar 2.3L T/C, 1984-88 T-Bird 2.3L T/C, 1987/92 Mustang 2.3L EFI. 0.5 Hr.
912507D Idle By-Pass Valve Cleaning - 1988-91 Tempo, Topaz 2.3L HSC, 1985-92 Ranger 2.3L EFI. 0.6 Hr.
912507E Idle Air By-Pass Valve Cleaning - 1986/87 Aerostar 2.3L EFI, 1985 Bronco II 2.3L EFI. 0.7 Hr.
912507F Idle Air By-Pass Valve Cleaning - 1986-90 Bronco II 2.9L EFI, 1986-92 Ranger 2.9L EFI. 0.7 Hr.
912507G Idle Air By-Pass Valve Cleaning - 1991/92 Probe 3.0L EFI, 1986-91 Taurus 3.0L EFI, 1987-91 Sable 3.0L EFI. 0.6 Hr.
912507H Idle Air By-Pass Valve Cleaning - 1986-91 Aerostar 3.0L EFI, 1991 Ranger 3.0L EFI. 0.7 Hr.
912507I Idle Air By-Pass Valve Cleaning - 1988 Continental, Cougar, Taurus, T-Bird, Sable 3.8L EFI. 1988 Cougar, T-Bird 3.8L S/C. 0.6 Hr.
912507J Idle Air By-Pass Valve Cleaning - 1990-92 Aerostar 4.0L EFI, 1990 Bronco II 4.0L EFI, 1991/92 Explorer 4.0L EFI, 1990-92 Ranger 4.0L EFI. 0.7 Hr.
912507K Idle Air By-Pass Valve Cleaning - 1987-92 Bronco 4.9L EFI, 1987-92 F-Series 4.9L EFI, 1987/90 Econoline (Without Rear Heater) 4.9L EFI, 1991/92 Econoline (All) 4.9L EFI. 0.7 Hr.
912507L Idle Air By-Pass Valve Cleaning - 1986-88 Cougar, T-Bird 5.0L EFI, 1986-87 Continental, Mark VII 5.0L EFI, 1986/91 Crn - Victoria, Grn - Marquis 5.0L EFI, 1986-92 Mark VII 5.0L HO, 1982-92 Mustang 5.0L HO. 0.6 Hr.
912507M Idle Air By-Pass Valve Cleaning - 1985-92 Bronco, E-Series, F-Series 5.0L EFI. 0.7 Hr.
912507N Idle Air By-Pass Valve Cleaning - 1988-90 Bronco, F-Series 5.8L. 1991 Econo, F-Series, Bronco 5.8L (Do not Clean Solenoid, Calib; 1-64E-R10,1-64H-R10,1-64J-R10,1-64K-R10,1-64M-R10,1-64P-R10,1-64R-R10,1-75A-R00,1-76A-R00,1-76B-R00,1-76C-R00) 0.7
912507O Idle Air By-Pass Valve Cleaning - 1991/92 F And B Series, 7.0L EFI. 0.7 Hr.
912507P Idle Air By-Pass Valve Cleaning - 1987-92 E-Series, F-Series 7.5L EFI. 0.7 Hr.
912507Q Throttle Body And Idle Air By-Pass Valve Cleaning - 1989/90 Probe 3.0L EFI. 0.9 Hr.
912507R Throttle Body And Idle Air By-Pass Valve Cleaning - 1987-90 Econoline (With Rear Heat) 4.9L EFI. 0.8 Hr.
912507S Throttle Body And Idle Air By-Pass Valve Cleaning - 1988-90 Econoline 5.8L EFI. 0.9 Hr.
912507T Service Kit Install - All Cars And Light Trucks (Except Aerostar And Econoline) - Refer To The Service Procedure Application Charts, For Vehicle Application. 1.0 Hr.
912507U Service Kit Install - Aerostar, Econoline - Refer To Service Procedure Application Charts - For Vehicle Application. 1.2 Hr.
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