engine stumbling

[carlos]

I'll be driving down the highway doing 100-110 kph and during accleration to this speed the engine will stumble and sound like it is running rough but goes away after about 20 seconds. the ses light will come on and turn off shortly, code 78(wastegate sol.) the truck seems like it got good power but is there something else i should be looking for?

[6.5SmokeStack]

have you tryed to replace the wastegate its self? that could be it