Posted by: @sc4ki8er4ty6

I have a 2008 GMC Sierra with a 5.3 Vortec, I have a Check Engine code P1174 Fuel Trim Cylinder Balance, I have 147,000 miles on trk. I'm also interested in how to reset my check engine light my self.

Once you fix the offending code, there is a drive cycle that needs to be redone, or, you can use an OBDII scan tool to reset the CEL. If it's not been properly fixed, the CEL will just illuminate again. 

Have you had these bulletins addressed?

https://workshop-manuals.com/gmc/sierra_1500_4wd/v6-4.3l/powertrain_management/prom_programmable_read_only_memory/component_information/technical_service_bulletins/customer_interest/08-06-04-028/apr/08/engine_controls_mil_on/dtc_p1174_set/

https://www.cadillacforums.com/attachments/gm-procedure-for-fuel-injector-cleaning-pdf.74427/

Use a diagnostic tool to obtain a cylinder misfire counts.

Remove any cold air intakes or other mods. Change the air filter. Clean the MAF.

test the fuel pump, fuel system leak down, and the fuel injectors.

Install new OEM O2 sensors.