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2004 GMC Sierra 1500 4.8Lgot P0171 and P0174 codes, Changed MAF Sensor, checked fuel pressure 60 psi. I still get P0171 and P0174 codes, and lack of power up hills
Optional Information: Year: 2004Make : GMCModel: sierraEngine: 4.8 L Already Tried: Changed MAF Sensor tested Fuel Pressure 60 psi
These have a big problem with the intake gaskets leaking and causing the codes and symptoms you are describing. This is a very common problem and replacing the gaskets is the fix for this problem. zzdaryl40201.8518008449
Experience: 28 years experience, Master Mechanic