5.3 with excessive crankcase vacuum and sputter

[Bodie]

I just bought a giant turd with a 5.3l on a stand alone harness. I am having problems with it sputtering so bad it wont even move when its cold. Once its warmed up it runs OK but feels low on power. I ran codes with a cheapo scanner and it gave me a PO405 and a PO452 which should be emissions codes. EGR valve and fuel tank vent.

It also has a lot of crankcase vacuum, like you can barley get the oil cap off. I wanted to see if anyone has a diagram of all the vacuum hoses as some are plugged, some are open, and some run into each other.

[Ray@NP]

what year 5.3L is it?

[George C]

what is it in? where are you located?

[farmtruc]

Our test engine had excessive vacuum also.
Pull the pcv hose and block the intake side.
Fixed.
Btw the oil cap would be tight and whistle with all that vacuum.