Some 2008-2010 Ford F-Super Duty trucks equipped with a 5.4L engine may exhibit a MIL on with DTC P2135. Various other DTCs may also be present. Symptoms may include intermittent rough idle, idle speed below specification and/or reduced power.
The concern may be attributed to the TPS (throttle position sensor). Follow the steps in the workshop manual, section 303-14A to replace the TPS. The replacement TPS is available as P/N 6L2Z-9B989-D.