2.3L ('83-'97) 1993 2.3L Loss of Power after warmed up

[93 Ranger]

Sorry for the long post. I just picked up this ford Ranger a couple months ago it is 1993 Ford Ranger 2.3l with a manual transmission. It would run fine in colder temps. But the other day when we started getting warmer temps around here and I noticed when driving the truck the other day after it got warmed up it starts loosing power, sputtering and when I take off from a stop it will start bucking sometimes. The check engine light works, but never comes on when the truck starts acting up. What I have done to the truck is:
When I first got the truck I cleaned mass air sensor, and the throttle body and I put new spark plugs in it and I also put new exhaust with new catalytic converter. The other day when it started acting up I changed the throttle position sensor, the ignition control module, changed the fuel filter and replaced the fuel pump. After I changed the fuel pump the problem seemed to get better but it still there. I’m getting tired of throwing parts at it with, little to no results. Any help is appreciated thanks.

 

[scotts90ranger]

If it's after the engine is warmed up, I would suspect the pre cat (there might only be the one...) oxygen sensor, it sounds like you have done everything else