Idle surge goes away when I pull off valve cover hose to intake

[Blu92]

I have an idle surge issue. I thought it may be from the throttle body so I took it apart and cleaned it, put in the fiav bypass plate and redid the shaft seals and all gaskets. After hooking everything back up it still surges. It's a slow surge. Idle will rise slowly and drop back down after about 5-6 seconds. I noticed that when I pulled the valve cover hose that goes to the intake by the air flow meter the surge went away. I also noticed that air was pushing out of the valve cover when at idle or if I give it gas. I looked at Calan's pcv article and it looked like it should be pulling in air at idle. Any ideas?

 

[Blu92]

Also I checked the pcv valve and cleaned it and it operates correctly. The car is pretty much stock except for full exhaust(2.5 to 3 inch downpipe, 3" inch cat and catback), and when I redid the timing belt I replaced the rear balance shaft with a stubby shaft and left the front one in and removed the belt.

 

[SasaniFab]

Im assuming that when you pulled the hose the idle also increased? Is the Fiav adjusted correctly? You are allowing more air into the engine, un metered air. Sounds like you need to adjust the biss and possibly tps.

 

[Blu92]

It actually dropped to normal, about 800 rpms. I got it fixed but I forgot how to mark the thread as resolved. There were a few things wrong so I don't know if one thing fixed it or a combination of them. I checked the pcv again and noticed it still stuck occasionally so I replaced that and added a check valve between it and the manifold. I also recently replaced the vacuum hoses and wasn't paying attention and hooked one of the purge solenoid hoses to the fuel pressure regulator solenoid. And my tee for the boost gauge was cracked and leaking so I put in a metal tee with hose barbs for the vacuum hoses and a push in connector for the gauge hose. Running great now.