GMC COMPUTER LIMP MODE - REDUCED POWER

What Is Wrong When I Have A "reduced Engine Power" Message On My 2005 Yukon

This Popped Up In Message Center “reduce Engine Power”. Now The Car Won’t Start And When I Put A Code Reader On It All Kinds Of Codes...

We’ve Replaced The Tbs, Tb, Pedal, Pigtail And We’re Still Having Problems With Reduced Engine Power. It’ll Run Right For A Minute...

Step On The Gas And Nothing Happens Doesn't Rev Or Anything Sits At Idle.