[ChevyGuy]

"Pending codes" (not quite sure what this means) P0301 Cylinder 1 misfire detected.

A pending code is when something is detected, but it hasn't reached the threshold to set the code. For example, if Code XYZ is set when condition ABC happens 5 times. But so far, it's only happened twice. So Code XYZ becomes a "pending" code.

 

[ChevyGuy]

I'm not up on interpreting numbers, but when I see "lean", my mind quickly thinks "air leaks".