Can an oil leak at the VCT cause lean codes?
 

I have an 06 F250 5.4 3v with 132500 miles which I have lean codes for both banks. I have replaced both cats, MAF, the vacuum elbow, the break booster vacuum lines and the throttle body motor and gasket. I can't find any other vacuum leaks but I am leaking oil at the driver side VCT can that cause any problems or what else can cause lean codes