Bank 1 and 2 lean codes

[kendrick newborn]

Hey everyone, I have 2004 chevy tahoe 5.3 and it keeps throwing bank 1 and bank 2 lean codes. The only thing that I've noticed is it has a inconsistent engine shake at idle, I did look for vacuum leaks but I haven't found any yet. Has anyone delt with this issue before? The only thing not stock is the previous owner installed a cold air intake

 

[strutaeng]

Lean on BOTH banks is usually a fuel delivery issue, especially when both banks fuel trims are identical and stay the same (or worse) under engine load.

 

[nonickatall]

So check first the fuel pressure. There is a connection on the rail for that purpose.

 

[kendrick newborn]

So check first the fuel pressure. There is a connection on the rail for that purpose.

It came on yesterday buy went off when I put gas in it, then after work it came back on

 

[nonickatall]

A common knowledge is, that problems which apears with cars or woman mostly not disappear from themself...

 

[Fless]

The OE air intake is already a CAI, so there's nothing to be gained by changing it to aftermarket, other than more noise under the hood and a potential dirty MAF.

In addition to the other suggestions of a vacuum leak or fuel pressure issue, I'd add that perhaps unmetered air is getting in after the MAF and before the throttle body. Carefully inspect that CAI plumbing for any leaks. Best thing to do is change it back to OE.

Also, the MAF may be dirty or may be reporting inaccurately.

A good bidirectional scanner and some knowledge about how the fuel trim system works would likely show the cause of the problem. You may need to see a good doctor.