I swapped out headlight bulbs Saturday which involved taking out the battery. I only drove the car about 3 miles after that Saturday evening to check out the new lights and buy gas. Did not drive it at all Sunday. Yesterday I drove to work, seemed normal on the morning commute, fairly tame in the rain but one high speed pass which seemed fine. Yesterday afternoon I was running a couple errands and it seemed soft on the low end, like slower to pull from around 2 grand up to 3 but then real quick from 3 on up, even to redline a few times. I logged most of the drive home on the AP and hit 14.3 lb of boost on one spirited acceleration, not what I would consider WOT, though. Still seemed that way on the way in to the gym and work this morning. I can see the revs climb, but it seems like it's not building boost, then whoosh, away it goes. No CEL, no funny noises.
This is an 06 WRX with a VF39 and supporting mods, Clark Turner e-tune, 4eat, just turned over 30k miles. It's only been 65 miles since I took the battery out. My thinking is this: either all of a sudden something has come loose and I've developed a vacuum leak, or my tranny has all of a sudden started slipping, or my ECU is relearning after I disconnected my battery. I recall that after I went to stage 1 and then stage 2 that it just seemed to get better as I drove it, although I don't recall that quite as markedly when I did the VF39 swap. So does this sound like it's just the ECU and all will be swell in a couple more days, or do I need to call my friendly mech and start trouble shooting?