Codes P0171 & P0174.

[kens57]

I have codes PO171 and PO174 come on but are not actibve. Any help?

 

[maguinness]

P0171/0174 indicates that the long term fuel trims have reached a maximum (should be somewhere around 30-35%). Fuel trims are how much fuel the PCM adds or subtracts. 0171/0174 indicates that the engine is running lean, meaning that outside air is getting past the mass air sensor. The O2 sensors see this excess air and the PCM responds by cranking up fuel trims to add more fuel for that more air.

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the EEC-V section. Check the intake manifold gaskets, vacuum lines, spark plugs, and cables.

 

[SoNic67]

I would check also the O2 sensors.