5.4L Suddenly sounds like a Harley with short pipes....
 

Okay, so my '02 Screw has been acting up lately. I know there is a slight miss from a worn coil boot, but that's been about the extent of it. When I got home last night, right before turning off the engine, the idle got really rough, but I chocked that up to the worn boot.

This morning my wife had to take my truck to work. She came back upstairs to tell me it's making a weird noise and smoking. I go down, crank the engine and it's LOUD! No smoke, but holy crap! I had to kill it quick, as it was 6am. Could I have blown my exhaust manifold or gasket? How can I check for this? Other than being loud, it seemed to rev okay, but I didn't attempt to put it in gear and move. If I do have a manifold problem, is it safe to drive? Any thoughts or ideas? Thanks!

Oh, I don't know if this is relevant or not, but the truck spent it's whole life in Texas. I just moved to the Pacific Northwest and these problems are starting up. Could the new wet environment be a contributing factor? Also, she's got 150k.

Did it eject a spark plug? Is it a loud ticking/clicking sound that is evenly timed like every time the cylinder is actually blowing the air/gas mixture out the head rather than combusting?

An ejected spark plug is a good question. The sound you describe is in fact what I was hearing before the super-loud exhaust issue started up. I know my dad has had issues with ejected plugs on his F250 w/5.4L. Do you think an ejected plug is more likely than a manifold issue? I ask only because it seems like the noise isn't coming from the side where I know my bad boot is.

It probably has nothing to do with the bad boot. The bad boot just means you are already down a cylinder, or at least a little power wise. This new noise could be totally unrelated.