Some 2011-12 Ford F-150 pickup trucks with 3.5-liter turbocharged engines may exhibit an intermittent stumble and/or misfire on hard acceleration. According to Ford, the symptoms typically occur after an extended cruise at highway speeds and only in damp or humid conditions, and may be accompanied by an illuminated or flashing check engine light with trouble code P0305, P0305, P0306 or P0430 logged in PCM memory.
Start your diagnosis by pulling trouble codes on the pickup truck. If you see P0430 on your scanner display, immediately replace the left bank catalytic converter with an updated unit, part No. BL3Z-5E212-E. Now head to the data stream and look at PIDs MFF_LOAD and MFF_RPM. Does the data indicate that the engine speed was above 2500 rpm and load was above 100 percent when the code(s) set? If not, this information doesn't apply; continue troubleshooting until the issue is resolved.
If the data does indicate those operating conditions were present when the code(s) logged, check for a deflector plate on the charge air cooler. If the plate is missing, install an upgraded charge air cooler, a new deflector plate and new push pins for the shield. These go by part No. BL3Z-6K775-B, part No. CL3Z-19E672-A and part No. W711281-S300, respectively. If the deflector plate is installed on the cooler, you'll have to have the PCM reprogrammed, then install the upgraded charge air cooler and the original deflector plate and shield using the new push pins.