BigHen

I have a 1994 454 7.4l Chevy p30 motor home gas engine. Idling when its first cranks up stalls, but revving the engine for about 2 or 3 minutes it stays idled for about 10 minutes then stalls again. Not sure if vacuum leak is the issue? Took PCV out or unplugged it from intake and cranked it back up Idling then works awesome at regular rpm's. But as I put CV back in it stalled. Tried the thumb over intake hole it sucked good so I don't believe its the intake gasket . Not sure what to do next? Also checked Idle control too it was clean and working. Any advice? Chevy Van was as close I think to what mine really is a P30. Really not geared for fixing motors so if any1 could please help I would be grateful to whomever