1993 Rodeo Hesitation when it gets warm

My vehicle is a 1993 rodeo 4x4 with a 5 spped manual transmission and the v-6 engine. It has about 140,000 miles on it. It started to lose power on exceleration only when it is warm. I cannot get it to go above about 4000 rpms. When I first start it up no problems for the first 10 or so miles. If I get out of first quickly and work my way to 4 or 5th, I can get to were I am going, but maximum speed is around 50mph. It idles just fine.

I have replaced all the plugs and wires, fuel filter, Catylitic converter, and all 3 coils. No one has a unit that can read codes going back to 1993 around here, so I am at a loss. I do not want to just start changing all the emmision controls. This vehicle is fuel injected. Seems the more I drive it, the worse it gets. Shut her down and start it up later and she runs fine again till it warms up. I am going to make a donation, becaue I realy need your help. No one around here wants to mess with it, because they cannot read the codes.

Most of the things in the book under troubleshooting seem like they are fulltime problems, vacum leaks etc.

Thanks in advance for any help you can offer!