the hose is providing vacuum to the EGR. When the engine is running, remove the hose and see if there is pressure coming from the EGR. There shouldn't be. If there is, replace it. Also, to answer your question about the hose, yes it can cause a poor idle. Take the hose off and take it to the local parts store and get a new one and replace it.
Let me know what you find.
Friday, February 27th, 2009 AT 9:59 PM