My 97 f250 is showing engine code 'lean bank one and two'. I have read many posts on the very same codes showing with others and found it very useful. Here's the rub for me however. Virtually all the posts I've read all involved a rough running engine accompanying these codes. My truck runs like a top, idles beautifully and no noticeable loss of power or hesitation etc. Can anyone explain why I have had this code for almost a year without the engine showing any crankiness. I've deleted the code a few times but it always seems to return. What gives? I would love to know which of the possible causes; ( intake gasket, MAF,o2 censor, PCV elbow or grommet, etc) is likely the culprit?
Anxious to hear all of your inputs.

 

I had that code on a car I recently traded for my truck and it was the gas cap. It wasn't getting a good enoh seal and was causing the code to pop up. I just replaced the cap and cleaned off the metal neck too. Easy way I saw was that it was all black on the neck, it should be shiny silver to show no dirt build up. It was cheap and fixed my problem.

 

First off to answer your question O2 sensors are used to see if the engine is running lean or rich. since its affecting both banks i'd start by looking for vacuum leaks and maybe try cleaning your MAF.