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P0172 code troubleshooting

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10K views 2 replies 3 participants last post by  SD_GR  
#1 ·
Apologies if this has been covered elsewhere but I couldn't find much recent on troubleshooting running rich.

A little background
  • 2010 WRX hatch
  • Currently running stage 2 tune with a COBB intake and full custom exhaust. AccessPort calls the tune "TP Stage2 CobbSF Intake 2010 WRX-REV13"
  • Recently replaced the radiator, did have some issues getting it bled but have now bled it for several hours overall.
  • Recently added a resonator to the exhaust which was previoulsy just hi-flow cat and no muffler
  • Recently replaced a troublesome fuel cap with a generic one from Autozone, just replaced that with an OEM Subaru one yesterday.

I have been getting a P0172 code for the last few days. Some drives she still pulls well, other drives, particularly stop start ones, she idles rough and has a noticeable hesitation puling through about 3600rpm. Definite gas smell outside the car on startup. Occasional stalls as she drops back to idle. I have one run from yesterday where it gave misfire codes on all four cylinders so I don't think it is an issue with one cylinder alone.

I've been watching AF Sens 1 Ratio on the AccessPort and I'm consistently showing between 11 and 21, never below 10. I don't have a sense of whether that is rich or not. Are there other things I could be watching or logging that might help me troubleshoot?

Going to go in this weekend to try to diagnose. On my list right now are vacuum leaks, O2 sensor, MAF sensor. I'm less inclined to think plugs because its across all four. Are there things that I have done that may have screwed up the mixture? I'm tempted to revert back to stock tune to try that. Are there any risks in that?

Thanks in advance for any advice!
 
#2 ·
Did you just buy this car with the tune already on it? By the name it sounds like it's a Torqued Performance tune by Eric Minehart. I'd at least reach out to him and get his thoughts, maybe he recalls this car and help point you in the right direction.
 
#3 ·
A PO172 is diagnosed the same was as a PO171.

I'd clean the MAF and do as you suggest.

Have a search for PO171 threads and check the FPR too.