I know my cars really well but I'm not too good in the engine dept. I have a 2000 SE 5spd and my SES has come on for about a 1 1/2 weeks, went off and a few days later came back on. I have a brick wall at about 4700 RPMS and smaller brick walls at a few other RPMS. I finally got the code pulled and it says "System Too Lean" (Bank 1) What exactly is Bank 1 and what is too lean?? Thanks a lot.

 

Bank 1 is referring to your o2 sensor located on bank 1. Your o2 sensor measures the ratio of oxygen in the exhaust gas. It does this is to determine whether the air/fuel ratio is rich, stoichiometric (perfect), or lean. In this case your o2 sensor is indication your car is running "lean". Which may be the result of a vacuum leak, a lost of fuel pressure, or possibly a faulty o2 sensor.

 

a loss of fuel pressure rings a bell......when i come home from highway driving, In the garage I can hear a wierd sound....(lower pitched, after awhile gains a little higher in pitch almost like a soft playing flute or tuba) almost like a little air trying to escape i couldnt figure it out but when I loosen the gas cap, it goes pssssssssssss lets pressure out and the noise stops....is there possinly a leak somewhere?

 

Wife's RX300 had a lean bank error code. I did some research on google etc.. and found that a common problem was the MAF's heated sensor causing this error code. The heated wire element gets dirty and causes the engine to run lean in one bank. Sure enough I pulled the element and it had a fine coating of oily dirt. The lexus maf element can be lifted out of the maf housing by undoing 2 screws. You gently clean the element with a Q tip and acholol. I put a new filter in and reset the ecu. Been golden ever since.

 

i thought about cleaning it but i heard it is very easy to ruin.....true?

 

You can look can't you? But Nissan MAFS are big pain as they have the screen. But I don't see why you can't take the maf out and inspect the element. It's free but it does entail you actually maybe turning a few wrenches.

 

does anyone know where "bank 1" is in 2000 maximas? i need to check it but do not know where to look. Thanks (and what should i look for)

 

I had the exact same trouble code 6-weeks ago. It was read by a very helpful Checker auto parts store in MN. I tested all the obvious stuff but couldn't solve the rough running engine or find any defective parts. I took it to the local dealer, it cost almost $900 to change all 6 ignition coils and the MAF sensor, not the O2 sensor which I had espected as well. Engine now runs great. Sent a letter to Nissan for a refund regarding the well documented defective igntion coil situation (www.petitiononline.com) but the request was refused. Considering the car only had 32,000 miles on it I was dissappointed.

 

I think there is a tsb for the o2 sensor when you get that code.