Engine bogs down for a while, almost stalls

I have a 1995 Mazda B2300 (Ford Ranger) with an I-4cyl 2.3L engine with 146k miles.

A very specific problem is occuring and I'm not quite sure what it is, it may either be a spark or fuel issue.

I drive almost every single day of the year and out of that, about 1-2 times each year I will be normally driving and my power will decrease significantly. Sometimes, this has resulted in my truck slowly losing power while I'm driving and usually stallling out by the time it slows to a stop.

Other times, I'll be sitting at a light and it's idling fine. When I go to give it gas, it bogs down to an unbelievably low idle ~2-300RPM's. I plunge my foot on the floor to give it gas to get the revs up and it doesn't make a difference. Slowly but surely, it either revs up back to normal, or it dies no matter how much or how little gas I give it.

When it stalls, I crank the engine and it turns over and starts, but with the extremely low idle and dies again.
Usually after a couple cranks on the key, it turns over, and I can get home or drive to where I need to go with low power but no more problems. After a while, it picks back up and I'm good for the next year.

It just happened to me again.

I recently changed my PCV valve and fuel filter. My truck has been doing this before or after the changes.

My next step is plugs and wires.

It has been giving me a lean mixture code for the past year. PO171
I have clean gas from Shell.

It had a fuel sending unit change a couple years ago, but the gas tank may be cracked somewhere.

Any suggestions?
I can't quite seem to find this same problem anywhere else.


Thank you very much!