My Ranger started doing this crazy loud jackhammer noise on the freeway. The motor feels like it lost a little bit of power, and there's vibration that increases when accelerating. The sound never goes away, even when idling.
Welcome to the forums.
Sounds like a valve problem or something to do with the valve train.
I would start with a compression test.
What it sounds like to me is the piston coming up on compression and the compression is leaking through one of the intake valves.
Or possibly the exhaust _ you would hear it through the exhaust pipe though and the sound appears to be coming from the engine bay.
When was the last time a new timing belt was put in it ?
Thankfully it was a simple thing -- a spark plug had 'exploded' and had come out of the socket. The wire was half molten. I have no idea why that happened (and I didn't suspect the spark plugs at all). But after changing the plug and the wires everything sounds as smooth as always.