2007 aveo idling problems HELP!!!

I have been having idling problems with my aveo for the past 3 months. When starting it first thing in the morning, the idle goes up and down and won't stay running unless I give it gas. The engine light comes on and the cruise control light blinks. There is also a clicking noise by the gas cover and we replaced the evap solenoid valve but that didn't fix the problem. We went to the dealer and they told us to replace the spark plugs, didn't fix it. We brought it to another dealer and they said it was the egr valve, they disconnected it and it ran better but still had the starting problem then would run ok. The idling problem is triggering the hold button which flashes and it won't go into overdrive and until it stops flashing you can't shut it off. We were wondering for any help so we can enjoy our car again! Thanks!