You do not need a valve job.
I am 99% sure.
Let me explain a trick to you. It's called the mechanic's stethoscope trick. Take a long screwdriver, pry bar, or something like that- you're going to use this to listen to what's going on inside your valve cover without removing it. Start the engine. Put the probe on the valve cover- the top of the motor where the spark plug coils are- but not too close to the coils. Now, cup your hand over the other end of it, and put your ear up to it. Now you can hear the whirring of the valve train inside the valve cover. You can even move it around to different points on the valve cover, but be careful not to get too close to the injectors or coils or you could pick up sounds from those.
No clicking huh? Well where is it? Why do all these "car guys" keep telling me it's valves, and then the idiots online tell me there is no adjustment to the valves? (there is no adjusting this valve train)
I've been working on cars for 20+ years, and it sounded like valves to me too. It's not valves- obviously, the stethoscope trick proves it. Now put your stethoscope probe on the intake manifold, and listen to it- there's that sound!
Your problem is something called tumble flaps. It's a flap inside the intake manifold that Ford uses to manage volume vs velocity for optimal air flow to the engine at any rpm. This enables your car to have good low end torque, but not sacrifice top end hp. Unfortunately, when the tumble flaps get old, they start to make noise- and it sounds just like valves. To fix it, you need a new intake manifold and a gasket. Mine has been making that noise since around 100k, and I now have 150k. You have some time to figure out what you want to do, and where to get the parts at the best price. You can check with our new vendor Village Ford
, and see what their price is. I would expect it to be $200-300 for the part. I don't know what someone would charge to replace it. You might be able to find a low mileage intake manifold in a junkyard from 05-07, or find one in our Buy, Sell, Trade forum where someone has removed the factory plastic manifold for a high performance aluminum manifold. That's what I did, and I paid $100 for mine. I just haven't had a chance to put it in yet.