2006 Subaru Outback 2.5 wagon P0171

[82Stang]

Hello, I've been chasing this code for a week or two trying not to throw parts at it and diagnose it correctly. Code p0171 can be a bunch of things from vacuum leak to O2 sensor MAF, Purge solenoid, PCV valve and on and on.

Started from air filter, inserted new paper air filter, making sure box was on correctly and tabs in at bottom. Pulled MAF, cleaned several times with CRC brakeleen, reinstered. Tightened hose clamps all the way up to the intake. Pulled PCV valved and cleaned, top end of hose that attaches to intake with a plastic fitting and plug, comes on and off rather easily. Not sure what to do about that or if it even is an issue. Pulled/cleaned purge solenoid valve too. New cabin air filter and clean out of passenger side dash because mice took control for a while. But I evicted them.

Check engine light keeps coming back after I clear, same code p0171. I use cen-tech OBD2/can reader. If I can have some help interpreting the findings, that'd be great. This short test was only at idle and wasn't totally warmed up, very cold out, so that may factor into it and I can do another test.

fuelsys1 cl
fuelsys2 --?
load_pct 14.5
ect 138
shrtft1 21.1
longft1 25.0
map 4.2
rpm 707
vss 0
sparkadv 15.5
iat 37
maf 0.00 ---didn't know why zero here?
tp 12.2
o2slocb1s12--b2s ?
o2b1s2 .795
shrtftb1s2 0.0
eq_ratb1s1 0.999
o2b1s1 2.793
eq_rat11 0.999
o2s11 -0.004

Lastly, I have a feeling either MAF or front o2 sensor so I have both of those coming. I even got Denso o2, so it won't cause an issue. So if you have any thoughts, I'd like to hear them. Thanks everyone.

[82Stang]

Thought I narrowed it down to either maf or o2 sensor. Installed new maf, car ran like crap. Barely idled in gear. Took out, reinstalled old maf. Runs fine. Maybe it's the O2 sensor. Or I have a vacuum leak I am not seeing. Sprayed tho, so TBC.

[82Stang]

Problem solved!

So far anyway. Didn't bother with O2 as I wasn't convinced it was going in that direction. After watching video of half hour diagnostic on this code with snap-on modis, I think kid was right. It all came back pointing to one thing. Purge solenoid valve. Installed new one and voila, no hard start after fueling. Rest I/M monitors and erased checked engine light. So far so good.