SES = Lean bank 1 and 2

any ideas, no detonation so Ive been drivin it. I changed the fuel filter too, since I upgraded to 44lb injectors, so I wanted to make sure it got there asap. But before I pay for a SnapOn tool to read exactly what it is, I figured Id get some ideas.

 

bad O2's???

 

i had the rears shut off so i only have the o2s

 

well, i just had a similar problem but the other way. mine kept tripping system too rich bank 1 and bank 2. when both banks go, it's usually the maf or the fuel pressure reg. It turned out that my k&n had too much oil and it coated my MAF with a thin layer. the sensor read crazy and messed with my a/f. I guess it could go lean too. I fixed mine with a can of sensitive electrical parts cleaner. but if you try it, be sure to let it dry out good before you run it! cured mine, just an idea. I guess both 02's could go bad at the same time, but not very common.

 

Do you have any way to view your fuel trims? I am guessing not being your comment about the snap on scanner but just figured I would ask.

 

...the MAF sensor is pretty common for setting lean codes (on a few different manufacturers), you could check there first.

You recently did a 6.0 swap correct? Might want to check for vacuum leaks or unmetered air getting in to the induction system also.

 

I'm with Bud...Check for vacuum leaks or a dirty MAF from an over oiled K&N. A big exhaust leak will cause the O2's to read lean as well. Good luck!!

Dave

 

Very good Points.