P0171 bank 1 fuel too lean. Anyone can help me with this code. I already cleaned my mass airflow sensor and it still running lean. Idk what else to do.

 

did you just installed aftermarket intake ? intake or exhaust leak , fuel , and so on. you need to do some data log . by the way you posted it on classified .

 

you can try all of the potential fixes.. leaks/new intake etc.. but mine required replacing the maf sensor entirely, how did you clean your sensor?

 

Thanks for response, just used MAF sensor cleaner

 

may I ask where you got your replacement MAF sensor? Subaru dealership? Or Online?

 

Just had same thing, at last tune, I was told my front o2 sensor was going bad, also my Cobb intake was a little loose, fixed the intake leak and decided to replace the front o2 sensor as well,then cleared the code. so far so good only ran about 10miles since but seems good.

 

thank you so much for the input, I figured it could be the o2 sensors, since I cleaned the MAF, no air leaks, and my intake is on tight. Where did you buy your front o2 sensor, and are the front and rear o2 sensor the same? I was on Rallysport direct trying to find a front o2 sensor all they had was wide band o2 sensors. My last resort just buy it at a local auto parts store.

 

I had this happen to me once and i cant remember if i had bad ignition coils or one of my tgv flaps was stuck kinda closed but just some food for thought

 

thanks man, I'll look into your advice if it's not the o2 sensors.

 

Honestly I was doing a little reading seemed to be the Subaru sensors worked best without defected ones and ones that malfunctioned, I found them at fast Wrx for 249$ but my local dealership had it at the same price and in stock so I got them there, I also think Bosch makes one for around 80$ less but it was worth it to me for the peace of mind. Only took about 45mins for install, as far as the rear goes I'm not sure

 

I believe I bought mine on amazon.. It was denso, same exact sensor as stock cars are equipped with, subaru will just charge you up the *** for an oem one..

iirc i also replaced my o2 sensor with the bosch unit to be safe, after both of those had been replaced I never saw the P0171 again, good luck

 

Smoke test your car before replacing any parts.