Came on out of nowhere today, Only mod I currently have is a T1R axleback.

P0171- Bank one to LEAN.

Cleared it w/ the scanner.

Didn't have any noticeable issues. - What should I do?

 

hmmm scary how many miles u got check ur EGR

 

just under 20K
its a 2010 Sport 5spd

 

shit dam crazy for it to go lean and u dnt got a intake right shit u make me worried now lol hahaah i got 2012 sport 15k miles nothing worng so far i hope lol i got intake and greddy axel back i clean ym filter every oil change

 

I had an intake on it. but put the stock back in like 2 months ago.

 

Probable Cause:
Large vacuum leak
Fuel system concern
Igntition system concern
MAF sensor faulty
H02S/AF ratio sensor fault" cuz thats what usually causes it

 

disconnet battery see if it goes away : / if not might be maf : / i hear alot about them being sens dam i should go bak to stock lol

 

also dubble check house make sure everything tight dubble check maf make sure it snug

 

something is loose or was loose behind the maf. a connection or hose is loose/not connected/split. its letting unmetered air into the motor the maf isnt accounting for, the motor is running lean as a result. given how crammed everything is in that area.....thats your issue.

 

Did you by this car with no wty? If not take it to the dealer.