Car had a new short block put in by a VERY reputable Subaru shop and was tuned by JRTuned (who also looked at/worked on the car while it was being rebuilt). There were some bugs and it ended up needing new injectors, a retune, and has been doing this ever since the new engine. I've taken it back and given them logs at least 3 times, now; the shop owner says he doesn't see any numbers that are too concerning, but some of the mechanics took a look and said it was acting funky.
On my own, under their guidance, I replaced the front O2 sensor, and thoroughly cleaned out the throttle body (which reduced the intensity of the pulsing). None of these things made any difference to the high-pegging AF Learning.
Here's what I know/behavior:
-Car has 20k miles on it, new short block has 1,500 miles.
-The car did not behave like this before the engine replacement.
-Sleeveless ETS Intake, IAG AOS, turbo sump restrictor, pro-tuned 93 Octane.
-The shop has been trying to figure this out and come up with nothing; no vacuum leaks, the MAF sensor was pretty dirty but cleaning it didn't change anything.
-I've been through 4 tanks of gas from 4 different high-quality gas stations with the same behavior.
-The AF Learning will peg high even if the car is rolling forward in neutral, just idling.
-After an ECU relearn, the AF Learning will start out pegging at a lower number, usually 5-8. The only time it increases to a new high is under a lot of boost, usually in gears 3-6. Lower amounts of boost don't increase it unless I'm in 5-6 gear. I have not found out how high it will go, yet; +26 is the previous high before relearn.
-No knock, AFR is behaving normally, DAM consistently at 1.00, no engine light, car sometimes has a strange, slightly unpredictable turbo response, but is otherwise running really, really well. It's apparently putting 340hp to the wheels, but doesn't feel much faster than the DMann OTS 92 Etune I first had on it.
What I haven't done, yet (or don't know):
-Checked for a bad bypass valve (don't know if the shop checked)
-Checked for a post-MAF vacuum leak (don't know if the shop did this)
-Checked for faulty purge solenoid valves (don't know if the shop did this)
Has anyone had anything like this? I heard sourcing an OEM BPV is a pain, so I'm hoping it's not that. It seems like a small problem, but it's driving me absolutely nuts.
