Short and Long Term Fuel Trim and lean codes: P0171, P0174

rgorke

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Camarillo, CA
I understand the basics of short and long term fuel trims and being able to identify potential problems using idle, 1500 rpm, and 2500 rpm levels. I have replaced leaking vacuum hoses and am now monitoring short term and long term fuel trims. I unhooked the battery and went through the PCM reset procedures (I believe correctly) but I still get long term fuel trims that range between 10-20% even with the short term fuel trims hovering being -4% to 4%. I even have the long term going up from, say 10% to 14% even when the short term hasn't gone above 5%.

A couple of questions...

Is this normal?
Have I not completely reset the PCM?
Is there something else going on? What am I missing?

To date: new fuel filter, new crankcase hose, new manifold hose assembly, several tank loads of injector cleaner. I also plan on doing another smoke test this weekend.

Thanks
 

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