So the problem is about 2 weeks ago my truck blew a plug out of the head. So i bought the kit that puts the sleve into the head and then the plug Threads down through that. Got everything back together put a new coil on went to start it and ran very rough. Touch the gas pedal and intantly died. Threw a code which was cylinder 8 misfire clead the code took the coil and plug out and everthing seemed fine switched the coil with one next to it to see if it was a bad coil and still runs rough no code this time. I then for some reason took off the crankcase beather tube that fits onto the pcv valve and the engine smoothed out but idled at 2000 rpms put the tube back on and truck dies there is a lot of vaccuum almost seems too much. Im lost!!! The weirdest part is it ran better without a spark plug in cylinder 4 than it does now. Its a 2007 150 4.6. Sorry for the long post and thanks in advance for the help.

 

Not sure if this is the same problem, but it may point you to a solution. My camry was doing this exact same thing (rough idle, died or choked horribly on throttle) a while back. Turns out, on the EGR valve was seeing too much vacuum. On the toyotas (not sure how ford does it) there is something called the VSV that controlls the vacuum to the egr valve. It was stuck sending full vacuum to the EGR, keeping EGR open and allowing alot of exhaust gasses into the intake. When I pulled the brake booster vacuum (comes off the same tree) - it ran much better because the EGR couldn't get enough vacuum to pull open.

Perhaps the PCV vacuum is doing the same thing - allowing more fresh air into the engine or reducing vacuum pull. Find your EGR and unplug the vacuum line from it. See if the idle clears up (it may idle higher). Put your finger over the disconnected line and your idle should drop back to normal.

This may not be your issue, but it sounds similar to me.

Hope this helps!