I've read around and I'm beginning to think its something to do with the timing belt / timing belt tensioner, second opinions?
One videos better than the other and you can hear the rough start better when its cold

https://www.youtube.com/watch?v=Hubc...ature=youtu.be
https://www.youtube.com/watch?v=8Pye...ature=youtu.be

 

If it is a 4.0l SOHC then yes, engine will need to be pulled out and new chains, guides and tensioners installed, but read to the end.

This was an issue on the 4.0l SOHC from '97 to '02 or '04, but newer designed parts are better, well lasting longer anyway, lol.
Explorer got the 4.0l SOHC in '97, you have the first year Ranger with the 4.0l SOHC, 2001

And unfortunately the ONLY way to get to the rear timing chain is to separate the engine from the transmission and pull it out.

So scary part is explained, you may be able to get rid of the rattle and rough idle by just replacing the rear tensioner.

Very good video here: https://www.youtube.com/watch?v=P4N5E_RfYpE

 

I appreciate the video, rear doesn't look difficult to replace, front looks like a hastle. However I've only had this vehicle for the past...21kish miles and this seems to have started rearing its ugly head in the past...10k or so. How much damage could already be caused? I don't drag race so none of that nonsense. I'm just wondering because from reading about tensioners failing it seems like the chain is already being fast tracked to doom as well. What with whipping around and slapping on metal. There seems to be lack of power, like when there is no exhaust back pressure, also it seems like a slight misfire once in like 15-20 seconds, barely noticeable unless you look for it. How costly is it for a dealer to replace both the front and rear timing systems/position them to spec?

 

Loose timing chain lowers compression so you lose power.

Stock Exhaust systems have no back pressure they actually have low pressure, but it is a popular myth.
To create "lower pressure" at the exhaust valves an exhaust system is designed to create a "velocity" in the exhaust manifold, smaller pipe into larger collector does this.
The smaller pipes velocity into the larger pipe causes a lower pressure at the exhaust valves on that bank, so as one cylinder's exhaust exits pressure at the other two drop, like a suction effect.
The myth comes from people using larger pipe sizes at the exhaust valves, reducing the velocity, and then having a drop in performance.
Wrong conclusion is that larger pipe has better flow so smaller pipe must have created back pressure and engine needs that.
Larger pipe increased pressure at the exhaust valve by eliminating the velocity created low pressure.

Engine needs to be pulled out so I would call for the price, but be sitting down when they tell you.

 

Update, upper tensioner was the main problem. Slapping sound is gone and now apparently it solved a problem with shifting past...third gear I think it was. Power is back. Appreciate the help folks

 

Well it was smooth sailing for a couple of days and,then all the sudden the trucks sounding like an old tractor or diesel. Any ideas http://youtu.be/kXPjTkdW2mI http://youtu.be/m4OXVGsu1zw

Also when pushing the accelerator above around 3k rpms it sounds like the motor is having a combustion problem? Would that be caused by an exhaust leak between the cat and muffler?

 

Timing chain would be my guess from past posts.

No, exhaust leak that far back couldn't cause any engine issues.