Picked up my girlfriends son a new car because he had a baby and his POS Cavalier wasn't safe enough. 2003 Audi A4 Quattro 1.8t. 130,000 miles but in mint condition. Took it to the dealer before buying and they said it had random misfires in 1 and 2 301/302 and lean bank 1. Said the cts needed to be replaced. And the throttle body gasket had a leak. They replaced the coils per recall. So I bought the car and changed the cts and TB gasket, new NGK plugs .032, previous owner had dealer replace almost all the rear vacuum lines and valves. Reset all codes and it idles great, runs smooth, more power, but for only about 5 min. Then the CEL flashes, and it idles rough. So while looking around online extensively and reading furiously, I decided to just post my issue. I was looking around the hood while it idled I was checking hoses and noticed when I pinched the lower hose coming out of the intake manifold, it totally smoothed out the idle and ran great. Had my lady sit in the car and watch the rpm's and they didnt change, just smoother idle. So here is a pic of the manifold. Hopefully you guys can help me out.
I pinched the hose on the lower left bung outlet. What is it and what could be the remidy in your opinion? Thanks a million!

Anyone? I'm thinking of pulling it, capping the manifold nipple, and letting the other hose dump to atmosphere. But I want to make sure it will not hurt anything or starve anything. I think its just a crank case vent to manifold. Is that correct?

id remove the whole thing an use gasket maker to seal what ever the nipple connects to! try putting some sort of clamp on it and drive it for a couple days! if the works just leave the clamp on.