Ok my truck is a 2004 5.3 with a sts kit at 5psi. I did the #42 lucas injectors, and a nelson tune. Keep comin up with bank 1 and bank 2 lean codes. Any idea what this could be? Allen Nelson told me to check for vaccum leaks. But I dont hear any leaks. Any ideas.

 

battled a similar problem yesterday, and this is how we found the leak..

https://www.performancetrucks.net/fo...d.php?t=418686

 

I ran into this when i did an injector swap. Pull them and put new o rings. It will be the bottom ones if u think this is possible, I mean done around the same time frame..