[Spidey]

Hello,
I have an 03 GT Turbo. Recently engine light came on and car ran rough at idle only. No other symptoms. Checked computer and code P304 (Misfire on Cyl 4) shows only.

Changed plugs... Still the same but after driving to parts store for plugs there is a loud whining whistle noise coming from the front right top of the engine. I visually checked all available hoses and gasket locations but nothing is obvious. weird thing is, the noise goes away from a loaded acceleration above 2KRPM. If I just gun the accelerator in neutral the noise remains. When I turn it off, the noise stops as soon as the engine stops. Seems like a air leak but I just can't find it. I have since changed the wires as well. (dealer purchased wires and plugs) I thought the noise was a belt but it emanates from the right side and all the belts are on the left. Oh yeah... No other symptoms at all. No overheating, no loss in accel, no nothing but a rough idle below 2KRPM and a very loud whining noise.

Anyone have an answer to this before I shove out the bucks to the dealer? I would love to avoid paying a lot of money for something I might be able to fix myself.

Thanks for your help.