questions 2004 suburban

Hello,
Have a few questions. 2004 5.3 flex fuel
Trying to find pcv valve, found it on the truck, but cant find it available anywhere. Does it exist???
Took truck in for some warranty work, and one problem was the stability light would come on after driving a few miles, but only after a hard start (#1 ignition relay dropping 8 volts, was hard starting after driving).
Dealer said it needed a software upgrade, which they did. But when I asked them what kind of software upgrade, they couldnt tell me. They said there was a bullentin out, and they downloaded software to scantool, than to truck, but didnt know what the upgrade was about. Does that seem strange or is it just me???????
Thanks for your thoughts.

Paul

PCV valve should be available from your GM dealer...some valves are fixed orifice valves and do not need to be repaced

as far as the calibration update goes, the calibration is for the condition described in the bulletin.
There are 3 different bulletins related to stability issues. Usually the latest calibration will address all of them.