2004 Escalade ESV

During acceleration or moderate load, the engine goes into "Reduced Power" mode and must be turned off to re-set.  It does it more frequently when pulling onto a highway, and the transmission shifts from 2nd gear to 3rd gear.  The owners manual mentions that one reason this message may be displayed is if the engine is overheating (this is not happening in our case), or it may be something with the throttle control. 
 
I''m hesitant to replace the throttle control when it may simply be a faulty temperature sensor or something else as simple.  Has anyone else experienced this, and what did you find was the cause?
 
 
thanks

"Reduced Power Mode" can be caused by several things. Electric Throttle Control - Pedal Position Sensor or Throttle Body most popular but neither is cheap. Code is likely stored. Diag at dealer maybe worth while si as not to waste money on unneeded part.