Engine Lack of power?

Well, I changed three of the plugs, 4-5-6, which I'm sure you know are just under the engine cover. My misfire codes were only on cylinders 4 and 5, so I wasn't going to tackle the intake manifold for plugs 1-2-3 just yet. I will have to see if the misfire issue returns when the weather is wet again.
Onto the low power issue, when I started the engine cold, I looked under the vehicle, and I could see exhaust steam coming from under the engine, I am assuming there is an exhaust leak at or right around the manifold area. Am I correct to assume this is where I am losing power due to lost compression, and where I am hearing the loud 'whooshing' sound when I push on the gas? It seems the sound is right behind my dash/firewall, so that would put it right at the manifold area.
Again, thanks for your help.

Sorry its a v6 3.0
and yes new sparkplugs gapped a.54
everything worked fine before I changed them but now it has a misfire it seems like
car idles at about 500rpms and as im driving the car jumps and shakes

The misfiring will send unburned fuel into the Catalytic Converter thereby clogging it. This is a common problem with Escapes. Don't drive it when misfiring and get the problem fixed. The wooshing sound might be a blown hole in the EGR. When dry and running fine. Try spraying water on the coils one at a time to determine which ones might be the problem.

The exhaust on the the car got loud and then it started running like it wasn't getting any enough power power and took a long time to accelerate over 25mph. After a couple days now it won't go over 15mph and the service engine light keeps flashing.