The fuel trims have prob reset, as well as the iac motor for idle control. There's a procedure, search ls1 idle relearn procedure. Something like get to operating temp and idle it in park and drive with ac on and off for 10 mins each.
Tried the VY idle relearn but doesn't make any difference. I am assuming it had to do with the fly by wire throttle not having a separate IAC valve.
Is there an idle relearn for the VE V8 as this may be closer for the VZ?