Hi there these two codes can be taken care of with a computer reprogramming done at the dealer I have attached the TSB on the topic and those codes. As far as the rich concern could be because of the programmer. Another common cause of a rich condition is the Mass Air Flow sensor located after the air filter, inspect this and make sure that there is no debris on the heating elemnt inside of the air tube. But I think that the programmer could give you these symptoms as they can cause trouble codes and it is possible that it wants to overfuel the engine. But here is the article on those two codes that have to do with the throttle body and the position sensor as you will see there is two codes there if the reprogramming does not work then you will need a new throttle position sensor I have attached the part number also. Thanks Steve
Some vehicles built 11/29/2004 and prior may exhibit the wrench light on with both P2106 and P2135 diagnostic trouble codes (DTCs).
Replace the throttle position sensor (TPS) following the instruction sheet included in the TPS service kit. Reprogram the powertrain control module (PCM) to the latest calibration using WDS release B36.11 and higher, or B37.2 and higher. This new calibration is not included in the B37 CD. Calibration files are also available at www.motorcraft.com.
Some 2005 F-150 vehicles equipped with the 5.4L 3-valve engine and automatic transmission, built 8/23/2004 through 1/15/2005, may exhibit a malfunction indicator lamp (MIL) on with diagnostic trouble code (DTC) P061B and/or P2106. This condition may occur during a cold start combined with a rapid transmission gear engagement.
Reprogram the powertrain control module (PCM) to the latest calibration level using WDS release B35.4 or higher. Calibration files may also be obtained at www.motorcraft.com.