how to fix P0171 obd code on 2003 GMC yukon denali -

Question

I seem t have change almost every part/sensor but yet the codes P0171 and P0174 keeps showing up. vehicles run but power surges when I accelerate

Answer 1

P0171 Fuel trim lean Bank 1

P0174 Fuel trim lean Bank 2

This is a lean condition when the vehicle surges. is there any misfire condition along with this code condition.? The main cause for this condition can just be one cylinder causing both Bank to go lean. this can be from one injector to one ignition. Try to isolate the condition  Here is way to isolate to determine which cylinder the offending lean coming from . clear the code and swap the front 02 sensor . and see if the misire moves from one Bank to the other if so replace the offendng 02 sensor.