It doesn't look like there is a new vehicle in my future for the next few years. I'm okay with that so I have a little extra to play around with for my 1993 Ford Ranger. Its a 2.3 liter four banger and its always been lacking in highway speed. How can I improve that? Also the bench seat it completely in need of replacement. Where do I go to get that done? Thanks in advance.

Have the plugs, air filter, & fuel filter(if easily accessed) been given attention lately?

You could maybe adjust tire size somewhat to get more top or low end on the highway?

A salvage yard(somewhere) will have a newer seat. Once acquired, you or a shop could put it in.

I had a 94 Ranger with the same powertrain, and it's never gonna be a powerhouse. But I changed the plugs and air and fuel filters, and it ran much better. I could run 75 on the interstate with no problems.
Also maybe check your catalytic converter. Mine got partially stopped up and it ran like crap.

My little late 80s Mitsubishi pickup (2.0 4cyl) seemed to have more power after I replaced all the worn, cracked vacumn lines under the hood.

Keep the tires at max pressure, carry no extra weight in the truck.

I had an '01 for five years. Thought it great after my stripped MightyMax.

Note: Alternator wiring harness was too short on this truck; spliced wires failed; got hammered by the "dealership".

Ditto on the catalytic converter. Just went through that a couple of months ago. But before you go through all the attachments to the engine check the compression.