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.
P0171, P0303, P0301, PFFE codes on my stage2 06 STi
- Thread starter Murdered Out STi Nerd
- Start date
I changed the upstream O2 and MAF sensors today. No more CEL, but it seems to idle kinda rough.
What is the rpm idling at?
Doesn't really hold a constant idle. It bounces all over usually between 800 & 1200rpm.
Took it out for 5 minutes today to see how it held up. It got the P0171, P0301, and PFFE again. So it's not the MAF or O2 sensors. Checked the cylander roughness with my AP, all are at 0 except #1 witch was at 30. I'm about to flatbed it to my tuner and see what he finds.
Will do as soon as I get back to it.
I got home and started searching, and found this. It appears that a sensor's nipple broke off leaving the hose that's connected to the intake manifold to leak freely. I pulled the broken nipple from the hose. The sensor is marked 5429 and is connected to my intake manifold, does anyone have any idea what it is, and where I can get one to fix the problem?Any online places sell it? My other vehicle is also down currently, and a stealership is 1hr away.
Got it out! It's so hard getting my big hands in there. 
You think that could be that could be the culprit to my CEL?
