P0171 Error Code - Thoughts, Ideas?

IGOTASTi

System Operator
Staff member
So our 2016 Subaru STi has 6000 miles and we took it to North Carolina this past weekend. It's tuned Stage 1 and has the Cobb intake on it and now we're getting code P0171 and the dealer won't touch the car which we understand why, but we can reset the code with the access port, but it comes back in a hundred miles or so.

We called two Subaru dealers and each one wants us to put back the stock intake and remove the access port which we think is retarded in our book.

Any ideas where to start at?

Thanks,
igotasti
 

TerrapinStation

New member
"The P0171 code means that, on the first bank of the engine, the fuel system is running weak or a vacuum leak exists near this side of the engine. A lean condition occurs when the engine either receives too little fuel or too much air."


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IGOTASTi

System Operator
Staff member
"The P0171 code means that, on the first bank of the engine, the fuel system is running weak or a vacuum leak exists near this side of the engine. A lean condition occurs when the engine either receives too little fuel or too much air."


Sent from my iPhone using Tapatalk

Hard to say why a 2016 STi with 6000 miles would do that. We wonder if it's a bad front 02 sensor or an MAF sensor has gone bad or dirty.
 

HolyCrapItsFast

Drinks beer!
Yeah these dealers are retarded.

This could be a myriad of issues stemming from anything like a vacuum/boost leak, bad sensor/s, Fuel Pressure Regulator, bad injector or others. I would start with a boost leak test and/or a smoke test to rule out leaks. That is the most common issue regarding P0171.
 

HolyCrapItsFast

Drinks beer!
Do you have a wide band gauge? If so we can do a little troubleshooting.
 
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