Clicking sound

Hey folks. For a while now I've had a clicking sound in the engine while running. At first I thought it was loose valve or something. I took it to the dealer he said it was air getting in the valve housing.
Well now the Check Engine light has come on and theres more noise coming from the engine that increases with RPM, but from a different area I haven't had the time to check exactly where yet. This noise is more hissy in nature and makes me think I've got a bad seal somewhere in the exhaust system.
I've read a few things that might be the problem (bad ERG valve, bad catalytic converter, bad seal in the exhaust manifold), but the post were covering other topics.
Any help would be great. I love this car almost as much as my old Omni GLH.
-BD8123

ok first of all what year make and model is the car.... but as for right now not knowing any of that a clicking sound could mean many things, such ass lifters or pushrods, a sticking egr valve etc. etc and as for the hissing sound check all your vaccum lines i have a 95 avenger and i had a hissing coming from my engine compartment and it was a vaccum line had disconnected, first check all the easily visibles and then try and get your hands dirty abit and search around for others and also do your best to track the hissing with your ears it should lead you right to the noise and you should be able to figure out whats going on... please lemme know how it goes... good luck! ~Mr.Avenger~

The biggest thing is, do you have a V6 or a 4 cylinder?If you could put your cars info in your sig block like mine and list all aftermarket upgrades that would keep you from having to post the information every time.