Noticed my car randomly running slightly rough at idle and shuddering when you let the clutch out at idle. Hooked up OBD scanner - short term fuel trim 25% all the time.
Interdasting. Spray carb cleaner at all the various hoses and connections - nothing really makes a difference. Unhook the PCV hoses that go to the valve cover, put them back on. Fuel trim now hovers at 8-14% at idle and car no longer judders.
I think I still have a slight air leak around the valve cover, because when I plug one hose and blow into the other one (when they're hooked up to the valve cover) I can feel the pressure escaping slightly and hear it, but I can't tell where exactly it's going.