2009 gmc sierra limp mode problem

[koooch27]

I have a 2009 sierra with a bad limp mode issue. I have in exact order changed the tps sensor, foot pedal sensor, had it reprogrammed at the dealership, new throttlebody installed and reset engine grounds all to no avail. Where do i look next?. any help would be awesome, the limp mode when activated has almost gotten me in a few accidents already. 

[CamGTP]

So what codes does it throw when it goes into reduced engine power?

[koooch27]

tps sensor / throttle body 

[richard wysong]

complete codes please

[koooch27]

P2135

[richard wysong]

so that code is for a voltage corelation problem which is more than likely a wiring/ connector problem. time to get the service manual out or go to Alldata and follow the diagnostic tree. Codes DO NOT mean replace parts!