1991 TBI 350 in my V2500 Suburban. She’s acting like the IAC is slow, like instead of the idle picking up to compensate for the vacuum pull for the brakes at a stop light or the power steering load in tight turns, it idles low and chokes out. When I unplug the PCV valve line from the front of the throttle body the problem almost goes away. New OEM PCV valve. New IAC from Napa. Also, if I plug the PCV port on the front of the throttle body, the truck dies instantly. Cold or hot. My old K5 had the PCV port capped and it ran like a banshee. When I changed the IAC I pulled the throttle body and cleaned the shit out of the passage ways. New gasket for the throttle body base and the air cleaner base. I’ve tested other vacuum lines and no change. I haven’t messed with the TPS, I did check voltage and it was normal, I haven’t done map sensor, or egr controller. I replaced the vacuum lines for my cruise control and cruise control works perfect. Truck has the 4L80e. Only code I get is for EGR at highway speeds. Engine doesn’t have blow by. Starting to get pissed at this thing, so if someone has some ideas here, it would be greatly appreciated!