[RocktimusPryme]

Thank you.

I cant say for sure, because Ive never ran a vacuum setup like that. But I think we are on the right track. Maybe when the relief valve activates or something like that, its triggering your system to start acting odd, just like a variable PCV was for mine.

I dont know if there are different orifice types available, or maybe adjusting your existing vacuum system so its at a higher pressure (Or lower) maybe it will be less sensitive? I would have thought you would still need a port for fresh air somewhere. Ill try to find some information on plumbing those systems later and see what we can come up with.

First thing I think I would do on your end is look up if you plumb a vacuum pump for a carbed system and an LS system the same way. If you would generally do it differently for the fuel injected setup I would do that. Because that was my fix. The LS engines wanted a fixed meter PCV vs the floating ball types used in classic cars.