Ford - Explorer :: 2003 - Rattling Right After Engine Is Started - Slow Acceleration As If Engine Has No Power

2003 Ford Sport Trac with 4.0L SOHC engine

I started having this problem after I decided to do a tune up because of another minor unrelated problem (start up taking 2+ cranks sometimes and fine when gas is full... I'm going to replace the fuel pump for that but not until i resolve the more pressing issue)

Before the problem I had spark plugs and wires (all but #3) replaced by my dad and he also put in some Fuel Cleaner into the gas tank. He took it to a local mechanic and had the mechanic replace the #3 spark and wire and check the others and also replace the fuel filter.

After that my car was taken to jiffy lube where engine oil was changed... as well something else but I dont know what because no one is able to tell me.... my dad had one of his employees take it and the employee took it upon himself to get other things done but he doesn't know what.

And then when I got my car back after the weekend is when this issue started.

First I noticed a rattling (like a plastic is caught on a fan blade and it is hitting something as it goes round and round) right after engine is started. And on the roads, when I try to accelerate, it will accelerate- but very slowly as if my engine had no power.

When I floor my gas pedal, the car will continue to drive at a constant speed and I can start to hear a really fast rattling which I am not sure if it is the same thing making the rattling sound I hear at start up.

I've gotten the following codes : 300, 301, 303, 316

I have since then had my spark plugs rechecked, wires for #1, 2, 3 and 4 replaced with another brand. There was no long term change but I have noticed that every time messed with the wires (when spark plugs were changed, when wires were changed and when sparks were checked... etc) for about 3 drives right after it the car feels more powerful and smooth and then it will go back to driving like crap.

I have also changed the CKP sensor (advice of the Auto Zone) and there has been no change.
I have also replaced the coil pack this weekend and no change.
I have bought the more expensive wires but didn't change them since 2nd set for 1, 2, 3 and 4 has not made changes.

Currently: Only thing I have more noticed is that the car when first driven, feels okay at start up. I can accelerate from 0 to 30 with decent power and time and as long as i dont floor the gas and only lightly depress the gas the car will continue to accelerate with decent power and speed.

However, anytime the engine is strained (like going up a hill) I loose speed. and AFTER any time the engine is strained, i will no longer be able to accelerate with decent power and time.

The car at this point feels like it it trying, almost sounds and feels gritty if that makes any sense, and if i try to at least keep speed, the engine sounds change but no increase in speed. At this point I usually just try tapping lightly on the gas and it will eventually get upto 30mph and of course more effort to go beyond and continually increase the speed.

It takes me a good few minutes for me to go from 0 to 35 and another few minutes to get upto 45. (Now everyone drives around me after a complete stop because I cannot even get to 20 right away like most normal working cars.)

I really would hate to replace one part at a time to play guess and check but I also don't know any true mechanics in the area that can really drive, listen and look and determine what exactly is going on without playing guess and check with every little and big parts that are involved. I have seen some people replace the intake manifold, O2 sensors, CKP/CAM sensors, cylinders...