After reviewing everything, it leads me to believe you have an intake manifold and gasket leak They can be very hard to locate and find. Therefore, you should have it smoke tested and suspect manifold gasket. However, before going to the expense, check for vacuum leaks. Behind the throttle body, you will find a vacuum hose that has a 90 degree bend in it. It is common for them to dryrot and leak from there.
The reason I am focused in this direction is due to this. If it was an engine misfire, you would be getting a code for a random misfire or a specific cylender.
There is one other thing I just remembered and looked up. There were technical service bulletins (TSB)from Ford regarding this issue. It basically required the PCM to be recalibrated. It was a long time ago, but it may have never been done to your vehicle. PLEASE NOTE: A TSB is not a recall. It is a reference for the mechanics to follow on commonly ocurring probvlems. What is listed below is a list of TSB's that are related to the symptoms you have. It will most likely not make sense to you, but I'm adding it so you can take it to a ford dealer to have it checked. That way they will know exactly what you are asking them to do and not waste time on other things. If this has already been done, I recommend checking for the vacuum leaks I discussed earlier in this post.
MIL LIT/DTC IN MEMORY WITH DRIVEABILITY CONCERNS
TECHNICAL SERVICE BULLETIN
Reference Number(s): 97-26-19, Date of Issue: December 22, 1997
Superceded Bulletin(s): 97-21-13, Date of Issue: October 13, 1997
Related Ref Number(s): 97-21-13, 97-26-19
HESITATION/SURGE - MIL ILLUMINATED - DIAGNOSTIC TROUBLE CODES (DTCS) P0133, P0135, P0141, P0153, P0155, P0161, P1130, P1131, P1132, P1137, P1138, P1150, P1151, P1152, P1157, P1158 STORED IN MEMORY - VEHICLES BUILT THROUGH 11/97
MALFUNCTION INDICATOR LAMP (MIL) - MIL ILLUMINATED - DIAGNOSTIC TROUBLE CODES (DTCS) P0133, P0135, P0141, P0153, P0155, P0161, P1130, P1131, P1132, P1137, P1138, P1150, P1151, P1152, P1157, P1158 STORED - VEHICLES BUILT THROUGH 11/97
ROUGH IDLE - MIL ILLUMINATED - DIAGNOSTIC TROUBLE CODES (DTCS) P0133, P0135, P0141, P0153, P0155, P0161, P1130, P1131, P1132, P1137, P1138, P1150, P1151, P1152, P1157, P1158 STORED IN MEMORY - VEHICLES BUILT THROUGH 11/97
STALL - LOW SPEEDS AND OR IDLE - MIL ILLUMINATED - DIAGNOSTIC TROUBLE CODES (DTCS) P0133, P0135, P0141, P0153, P0155, P0161, P1130, P1131, P1132, P1137, P1138, P1150, P1151, P1152, P1157, P1158 IN MEMORY - VEHICLES BUILT THROUGH 11/97
LAMP - MALFUNCTION INDICATOR LAMP (MIL) ILLUMINATED - DIAGNOSTIC TROUBLE CODES (DTCS) P0133, P0135, P0141, P0153, P0155, P0161, P1130, P1131, P1132, P1137, P1138, P1150, P1151, P1152, P1157, P1158 STORED - VEHICLES BUILT THROUGH 11/97
Model(s): Ford Light Truck: 1997-98 Expedition, F-150, F-250 LD
Lincoln-Mercury: 1998 Navigator
Bulletin No: 97-26-19
Date: December 22, 1997
Calibration: 7-46D-R07, 7-46E-R07, 7-46F-R07, 7-46R-R07, 7-46T-R07, 7-46U-R07, 7-46F-R10, 7-46U-R10, 7-48J-R05, 7-48U-R05, 7-48J-R10, 7-48U-R10, 8-46D-R05, 8-46E-R05, 8-46F-R05, 8-46R-R05, 8-46T-R05, 8-46U-R05, 8-48J-R05
NOTE:This bulletin supersedes Technical Service Bulletin 97-21-13 dated October 13, 1997.
WARNING:This modification is authorized only for the listed engine. Performing this modification on other engine calibrations is unauthorized and could create liability under applicable federal or local laws.
The Malfunction Indicator Lamp (MiL) may illuminate on vehicles with a 4.6L or 5.4L engine, and one or more of the following concerns may be present:
MIL lamp on with Diagnostic Trouble Codes (DTCs): P0133, P0135, P0141, P0153, P0155, P0161, P1130, P1131, P1132, P1137, P1138, P1150, P1151, P1152, P1157, P1158
Stall at idle
Stall at low speeds
This may be caused by the Heated Exhaust Gas Oxygen (HEGO) monitor calibration not allowing enough time for proper monitoring.
Reprogram the Powertrain Control Module (PCM) and replace the HEGO sensor(s). Refer to the following SERVICE PROCEDURE for details.
Perform normal diagnostics as outlined in the 1997 Powertrain Control/Emissions Diagnosis (PC/ED) On-Board Diagnostics II (OBD II) Service Manual and repair as required.
If the concern still exists or no problems were found, reprogram the PCM using Service Bay Diagnostic System (SDBS) or New Generation Star (NGS) Tester. Refer to the following RECALIBRATION CROSS REFERENCE CHART for correct PCM calibration.
Replace the HEGO sensor(s) (F88Z-9F472-AB) as required.
NOTE:For 5.4L applications, dealers must also perform TSB 97-26-17 to install the drain tube on the lower A/C evaporator drain.
RECALIBRATION CROSS REFERENCE
Year/Engine SizeOld CalibrationOld Part Number (-12A650-)New CalibrationNew Part Number (-12A650-)
1997 - 4.6L7-48J-R05 7-48J-R10 7-48U-R05 7-48U-R10F75F-AEB F75F-AEC F75F-XB F75F-XC7-48J-R10 7-48J-R10 7-48U-R10 7-48U-R10F85F-TC F85F-TC F85F-UC F85F-UC
1998 - 4.6L8-48U-R05 8-48J-R05F85F-UB F85F-TB8-46U-R10 8-48J-R10F85F-UC F85F-TC
1997 - 5.4L7-46D-R07 7-46E-R07 7-46F-R07 7-46F-R10 7-46R-R07 7-46T-R07 7-46U-R07 7-46U-R10F75F-ZD F75F-UD F75F-ACD F75F-ACE F75F-AAD F75F-VD F75F-ADD F75F-ADE7-46D-R07 7-46E-R07 7-46F-R10 7-46F-R10 7-46R-R07 7-46T-R07 7-46U-R10 7-46U-R10F7PF-ADA F7PF-AEA F7PF-AFA F7PF-AFA F7PF-AGA F7PF-AHA F7PF-AJA F75F-AJA
1998 - 5.4L8-46D-R05 8-46E-R05 8-46F-R05 8-46R-R05 8-46T-R05 8-46U-R05F85F-AAB F85F-ZB F85F-ACB F85F-ABB F85F-VB F85F-YB8-46D-R10 8-46E-R10 8-46F-R10 8-46R-R10 8-46T-R10 8-46U-R10F85F-AAC F85F-ZC F85F-ACC F85F-ABC F85F-VC F85F-YC
NOTE:PCM replacement is not authorized by this TSB. Refer to the Powertrain Control/Emissions Diagnosis (PC/ED) Service Manual for appropriate diagnostic procedures if PCM hardware concerns exist.
Obtain an Authorized Modification Decal (FPS 8262 - obtainable through DOES II, 25/pkg) and list the date, dealer number, and summary of modifications performed. See Fig. 1. 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 NumberPart Name
F88Z-9F472-ABHeated Exhaust Gas Oxygen (HEGO) Sensor
Monday, January 17th, 2011 AT 4:36 AM