2009 Legacy very sluggish

[awsmdad]

130k mi, NA engine, 5spd

Idles fine.

Very sluggish acceleration. Engine bogs down then surges a little, improves slightly around 3K RPM but has a hard time spinning past 4K. Little better when cold. Gets worse as engine warms up. At normal temperature, car has hard time getting to 60MPH.

No CEL.

Already changed plugs, wires, coil pack, both O2 sensors, MAF, PCV, disconnect battery overnight, idle for 15 min with and without AC. No change.

Enclosed screenshot from OBD2. Shows pulling up to intersection in first, then accel in 1st, 2nd and into 3rd. Pedal on floor. Took about minute to hit 40 MPH.

MAP next.

Any thoughts would be appreciated

 

[bmart]

Did you diagnose anything first or swap all of those parts possibly introducing additional issues? Sounds like fuel without much to go on. What is the fuel flow rate?

 

[awsmdad]

Started with coil pack plugs and wires (been years since plugs changed). Went to O2 sensors and MAF next and PCV this AM. Symptom unchanged (what it is doing now is what it was doing before changing parts). Agree, feels bit like accelerator pump or choke on carburetor - if it had a carb.

 

[bmart]

OEM coils and wires? If not, I'd junk the aftermarket and get OEM. The aftermarket stuff is crap right out of the box. Did the ones you took off test as bad?

It is always the same, air-fuel-spark. The more you can rule out, the better. The more you touch without diagnosing, the worse.

 

[awsmdad]

Took out first O2 sensor. Ran much better (and louder). Looks like plugged cat.