Hesitation, Sag, Stumble

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Test the fuel pressure. Refer to Fuel System Diagnosis (Without FPCM) , Fuel System Diagnosis (FPCM) .
Test the generator. Refer to Symptoms - Engine Electrical . Repair the charging system if the generator output voltage is less than 9 volts or more than 16 volts.
Test the manifold absolute pressure (MAP) sensor. Refer to DTC P0106 .