My 2004 mini cooper s idles like crap with the pcv hose connected to the pcv valve....but perfect when disconnected. I pulled the pcv off and cleaned with cleaner, it sounds to be operating fine internally.

Im going to order another pcv valve and see if that fixes it. In the meantime, can the car be driven with this hose disconnected?

I already cleaned the throttle body, tmap, and map sensors.

There is an SES light on, code P1237 for upper intake manifold pressure....from the research ive done on here i feel like im running out of ideas.

 

And i should note, my mini has the Threaded style pcv valve