Hi everyone, first post here but I've been a long-time lurker, whenever I need a DIY guide for my truck this is the spot. However, today google and the forum aren't doing it for me. I don't much like taking her in to the mechanic I'm more of a do-it-myself with friends help kinda guy. That being sad she's not doing so well.

'99 Ford ranger XLT 4.0 6cyl with 201k miles on it.

About 7k miles ago (when I got the truck) I replaced spark plugs, wires, fuel filter, and made sure everything else was running well, just replaced the coil pack and planning on doing spark plugs and wires but I was also wondering if I even need to do that after 7k miles? Is it possible a bad coil pack ruined the plugs/wires sooner than they should have and will the bad plugs/wires make the new coil back go?

Currently on the list is power steering pump, serpentine belt, and now fixing this issue.

So basically here's the average bad day of running some errands with my truck:
Truck fires up great, but the idle is real rough, stepping on the gas smooths it out a bit but it returns the more I step on the gas, unless I am on the road.
While driving the truck will get reeeeeal shaky accelerating to go uphill out of my road going about 10mph. Driving 35-45, same thing. Acceleration causes extreme shakes. However, all this shaking goes away if I press a little more on the gas. Same situation on the freeway but more pushing speeds of 65-70, sometimes 75+ in a 70+ zone. Hard to push her past 80mph yet I used to be able to no issue.
Now I'm at the store, I do my grocery shopping for about 30-60 minutes, come back to my truck and start 'er up, lo and behold it will not fully start! The truck will hesitate to start unless I press on the gas slightly. It might even stay on for a little on its own but it will eventually clug and shake along for a few seconds and then dies out if I let off the gas. Pressing on the gas while starting definitely lets the truck stay on while it's pressed, and hell I can even run the AC, but if I let off the gas it will come to a near death until it finally caves and dies. If I try to back out and stop while keeping it alive with the gas, it usually dies before I actually come to a full stop in reverse(or drive if I am pulling out.) I usually wait about 30-60 minutes and try starting it up again to see if it starts like normal. If I'm in a huge rush I sometimes force it to go by popping it in neutral at every stop and revving the engine, otherwise it dies. Eventually after driving for a while it might keep itself on but I can't tell when that will happen. This is all accompanied by shaking that has gotten progressively worse over a couple months.

Oh and I notice it seems to happen more on the hot days though my truck doesn't seem to be overheating, and it could be from running A/C or cold air on those days. But other than that it has happened on a perfectly rainy cold day before but the problem is totally intermittent.

I don't have an RPM meter on the dash but I'm pretty sure the RPMs are too low to keep the truck running through the alternator, while giving it gas gives enough RPM to keep it alive. But why would the RPMs be so low at idle or stop?? Not to mention how rough it is!


Any help would be really appreciated as I've been scratching my head at this for months!
Thank you!!