I just pulled the Codes P0171, P0303, P0301, and PFFE on my 06 STi. Mods are CobbAP, Cobb intake, Cobb DP, Crawford Gymkahana catback, Spec Stage 2+ clutch, Clutchmasters streetlite flywheel, and Perrin TIP. The car isn't going to drive until it's fixed. It also is on a freshly rebuilt block with 10k miles on it. I had just ordered DW850 injectors, WB 255lph pump, Cobb ebcs, and an ETS TMIC for a protuned setup, but those parts weren't installed yet. I'm dreading that I already have a bad ringland and need a rebuild. I ordered a new MAF and upstream O2 sensor hoping that that might be the quickfix, but I'm starting to doubt it.