Go buy a Chilton's manual for your truck and figure out how to get to your instrument cluster, then study the wiring diagrams included in the manual that apply to "your" model and locate every ground and double check to make sure that the ground to chassis is good.
There are ten million people having the exact same problem with their vehicle, especially GMC and CHEVY..... And out of those ten million people there are maybe 1/10th of one percent who have been able to fix this specific problem by replacing one or another of the sensors or other miscellaneous parts that everyone has been suggesting.
Reasonable conclusion is that there is either a bad ground, or a dead short that takes power away from the injectors due to an incorrect signal coming from the ECM.