My check engine light came on with a code of PO 171. This is system too lean bank one. I was told it was a faulty O2 sensor but I have already replaced bank one sensor one O2 sensor. Has anyone had this problem and figured out what it could be. Please help me out with this code. Thanks I appreciate it greatly.

Mike

 

every single time i have seen this code, it has either been a air leak or a bad maf. typically, i do not suggest to just purchase a part without further proof but have seen this so many times. a new maf has resolved just about every 0171 that i have seen on the org in the 5th forum.

 

its probably a vacuum leak. you can check your vacuum lines underhood by spraying carb cleaner and seeing if the engine surges.

 

http://forums.maxima.org/showthread.php?t=374481