P1174 getting code 1174. How do you fix it

Where did you get code? whomever ran diagnostic should have told. Anyone can buy a $19.00 scanner, and still not code meaning, All Vehicles in North America use OBD2 codes and you can look online by typing P1174 code. the results are free. It took about 5 seconds to find answer..
https://www.autocodes.com/p1174_chevrolet.html

https://www.engine-codes.com/p1174.html
https://www.troublecodes.net/gmcodes/p1174/

You may have a fuel injector problem.- try a good fuel system cleaner.

There is a technical service bulletin that states the correct procedure to repair this issue is to replace the injectors with updated units AND reprogram the pcm for the new injectors.

Please go to this web page.
http://engine-codes.com/p1174_honda.html

The 455 and 1174 are probably related to the same issue---emissions and air to fuel mixture which could be a purge valve for the evap. system and the 521 is usually a bad oil pressure sensor.

You may need a shop manual to get the testing procedures.
Code 303 is for a miss on cylinder 3 which could be ignition or fuel related.
Code 1174 is for a problem with the fuel trim which could be due to the problem with cylinder 3 or something else.

Year make and model ?
Code 170 is for a lean or rich fuel mixture on bank one.
Code 301 is for a miss on cylinder one which could be fuel, ignition, or something mechanical.
Code 1174 depends on the vehicle.

trouble code p1174 for 2008 chevy 1500? P1174 indicates fuel trim cylinder balance malfunction.

1174 is a lean code, and would have to been set first because it will not set when the 0300 is there. 0300 is a random misfire, because it read after the lean code, it was probably caused by the lean condition. 1st check for vacuum leaks from hoses or intake gaskets, you cal listen for a hissing sound, or spray carb cleaner around intake systems, a change in rpm will be noticed when spraying near a vac leak. other probable causes are the upstream 02 sensor, map sensor, or fuel delivery problems. does the vehicle idle porly, or does it miss at the top end?