P0171/p0174
 

2001 Saturn L300 just bought it only has 77k miles on it. Has two fault codes P0171 and P0174 service engine soon light is on. Anyone know where I should start looking? I want to go ahead and get it inspected.

Those are air/fuel mixture codes. Either you're not getting enough air or too much fuel to the engine. Check your air filter and hose for restrictions first. Maybe get a bottle of Techron Fuel System Cleaner and a run a tank of gas with it in there. You might have a sticky or dirty injector.

got it. I put some Lucas in it as well as some guaranteed to pass. Tank of premium. Gonna let that burn through it. I cleaned the mass airflow sensor and the code still came back. Haven’t put many miles on it yet so hopefully after I replace the MAF and let some fuel go through it, itll correct itself.

Replace the fuel filter, and inspect for vacuum leaks after the MAF sensor. Check the six intake boot clamps. With both lean codes it could be a MAF sensor itself. I have factory diagnostic manuals to help diagnosis.
Andy

Premium gas will do nothing for this. You need to look at load values on the scan tool.

Did you resolve the P0171 & P0174 Codes by replacing the MAF Sensor? If so, did you use an aftermarket OE standards part or AC Delco?