And this is the TSB;
3.5L GTDI—INTERMITTENT STUMBLE/MISFIRE ON TSB 12-10-19
ACCELERATION FROM HIGHWAY CRUISE IN HUMID
OR DAMP CONDITIONS WITH POSSIBLE DTC
This article supersedes TSB 12-6-4 to remove the production fix date, update the Title, Issue Statement, Part List and Service Procedure.
Some 2011-2012 F-150 vehicles equipped with a 3.5L gasoline turbocharged direct injection (GTDI) EcoBoost engine may exhibit an intermittent engine surge during moderate to light loads at cruise, stumble and/or misfire on hard acceleration after an extended drive at highway speeds during high humid or damp conditions. This could result in a steady or flashing malfunction indicator lamp (MIL) with diagnostic trouble codes (DTCs) primarily for misfire P0300, P0304, P0305, P0306. DTCs P0430 and/or P0299 may also be present.
Follow the Service Procedure steps to correct the 4ondition.
[COLOR=blue! important][COLOR=blue! important]Insure[/COLOR][/COLOR] all hard fault powertrain DTCs are addressed prior to performing the calibration update.
1. Check for DTC P0430. Is DTC P0430 present?
a. Yes - Replace the left [COLOR=blue! important][COLOR=blue! important]bank[/COLOR][/COLOR] catalytic converter assembly. Refer to Workshop Manual (WSM), Section 309-00. Proceed to Step 2.
b. No - Proceed to Step 2.
2. Is the Charge Air Cooler (CAC) equipped with an air deflector plate?
a. Yes - Proceed to Step 5.
b. No - Proceed to Step 3.
3. Install a new CAC, new air deflector plate, and original shield using new retaining pushpins. Refer to WSM, Section 303-12. Proceed to Step 4.
4. Reprogram the PCM to the latest calibration using IDS release 79.02A or higher. This new calibration is not included in the 2012.5 [COLOR=blue! important][COLOR=blue! important]DVD[/COLOR][/COLOR]. Calibration files may also be obtained at www.motorcraft.com
5. Install a new CAC and the original air deflector plate and shield using new retaining pushpins. Refer WSM, Section 303-12.
PART NUMBER PART NAME
BL3Z-5E212-E Catalytic Converter Assembly
W520514-S440 Nuts (2 Req)
CL3Z-19E672-A Deflector Plate
BL3Z- 6K775-B CAC .
W711281-S300 Push Pin (2 Req)