Engine - Hesitation/Stumble
85ford05Article No. 85-5-29 (Formerly 85-4-36)
HESITATION/STUMBLE - 4.9L UNDER 8500 GVW
LIGHT TRUCK 1984/85 E, F, AND BRONCO
CALIBRATIONS: 1984 - All, 1985 - 4-51R R00, 4- 51S R02, 4-51T R00, 4-52G R00, 4-52G R10, 4-52L R00, 4-52L R10, 4-52R R00, 4-52S R00, 4-52S R10, 4-52T R00
This is a reissue of TSB 85-4-36 to correct the water outlet part number.
The above vehicles may experience hesitation and/or stumble caused by too high EGR flow when the EGR valve initially opens. This may be especially noticeable in cold weather. To service this concern, revise the EGR system as follows (See Figure 31):
1. Install a new water outlet connector E5TZ-8592-E for 1985 and E0TZ-8592-B for 1984 vehicles, use gasket E5TZ-8255-D for 1985 only.
2. Install a new 160~F 3-port PVS D5AZ-8A564-A (yellow) into the water outlet connector.
3. Disconnect the EGR vacuum line (green) at the EGR valve and attach the line to the bottom port of the new PVS.
4. Install a 5/32" vacuum line from the middle port of the PVS to the EGR valve.
5. Install a tee (373846-S) in the vacuum line to the carburetor EGR port and install a 5/32" vacuum line from this tee to the top port of the new PVS.
6. Cut the vacuum line from the port of the new PVS about 3" from the PVS and install a vacuum delay valve D3TZ-12A091-C (grey/black) with the grey side toward the PVS.
Authorized Modifications Decal:
Obtain an Authorized Modifications decal and list the date, dealer number and summary of alterations performed. Select a prominent place adjacent to the Vehicle Emission Control Information decal suitable for installing the Authorized Modifications decal. Clean the area, install the decal and cover it with a clear plastic decal shield.
PART NUMBER PART NAME CLASS
E0TZ-8592-A Water Outlet A
E5TZ-8592-E Water Outlet A
E5TZ-8255-D Gasket B
D5AZ-8A564-A 160~F PVS AM
373846-S Vacuum Tee BR
D3TZ-12A091-C Vacuum Delay AM
OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: SP 9475A85
TIME: F Series - 0.7 Hr., E Series - 0.8 Hr. DLR. CODING: Basic Part No. 12A091 - Code: K2