I have a 2000 maxima SE and i keep getting a system too lean bank 1 OBD code. I have changed my O2 sensors and maf sensor but it keeps coming on with the same code. I had a aftermarket intake in it but my bank one O2 sensor kept going bad any ideas on that too? Well if anyone can help or if anyone has had this problem let me know what the problem is. Thanks

 

typically the maf is the cause of the that code. is it 0171? have you checked for any vacuum leaks?

 

sloppymax - if the MAF was bad, wouldn't both banks be affected?

Since the OP has already replaced the O2 sensors and MAF I would recommend testing the injectors...

 

injector(s) could definetely be at fault. a bad maf may cause both banks to run lean but for whatever reason, most people on here just report the one code of either 0171 or 0174. not sure why both dont show up but the majority with either code replaced maf and called it a day.

 

I havent replaced the MAF sensor but i cleaned it with throttle body cleaner b/c that is what i was told to try. My light did go off after that. Before that I did have 2 codes PO171 and PO 174. But I have replaced the bank one O2 sensor many times. Also how would I go about checking for a vacuum leak? Also I put that stuff in my gas tank to clean the injectors and all of that stuff. So what do you guys recommend? Thanks again for you help.

 

Also how would I test the injectors? I am trying everything because I dont want to take it to the dealer and pay $77 an hour for them to tell me.

 

you can check for vacuum leaks by checking clamps and gaps in the intake since its aftermarket. if there are no apparent leaks then i would bet replacing the maf will solve it for you. cleaning typically works when there is no cel and it has buildup on the actual wire.

 

If you had both P0171 and P0174 then I'm seconding sloppymax's opinion. It's time for a new MAF. Call Dave Burnette (number is in the Parts sticky) for a good price and good service.

 

id check the fuel trims, of course. you will likely end up replacing the MAF...

 

It is the factory intake. I took out the aftermarket intake a while ago because i was told it was causing the o2 sensors to go bad which i dont understand but oh well. So everything is factory. But maybe i will try to change the MAF sensor hopefully that will do it.

 

maf should do the trick and an aftermarket intake will not make the o2 sensors go bad.