i having problems with a message that says reduced engine power. how can i fix

I posted the answer!... With proper testing, the problem can be FIXED!... Guessing at what the trouble is not a solution!!! Be wrong every time..

Your answer is telling me to take it to get diagnosed and that's really not an answer! I have already had the truck at the Chevrolet dealership, they diagnosed the problem as bad throttle body replaced it and didn't fix! Then they said its in the wiring harness and replaced that and not fixed! Then they said it was a bad ground connection, so cleaned the ground and still not fixed!

Without a crystal ball...That's the ONLY possible answer over the Internet! Obviously the right person didn't do the testing and repair! Just the way it is..

Well I'm 'positive' that is exactly what's wrong with this one!!!!!