1993 Toyota Corolla When it gets warm it won't run right

Hi and thanks! When I first bought my car about 10 mo ago, I noticed a slight stuttering kind of hesitation when I was on the freeway in the upper power band, it was not bad and would recover quickly and run fine. I blew it off as to needing a tune up and delayed the tune up. As the months went by, this stuttering or jumpy hesitation continued to get worse mostly in the upper power band with a load on it. Then it started to hesitate and run with a jumpy kind of loss of power until I did not trust it on any busy street anymore. As it got worse it became evident that there was a connection between the car being cold and warming up. When it was cold it ran perfect, no problems but as it got warmed up I would get a very definite, hesitation driving it anywhere.
It continued to get even worse and I then on some advice I replaced the O2 sensor. This did not help much and I am on limited income so could not afford to take it to a shop and on side streets I could get by running it.
The other day a friend and I were looking at it and he suggested that I change the cap and rotor, which I did (they only go on one way and I confirmed that the firing order is correct). It ran for a few minutes poorly and the next day it would not even start. Note: I have checked and changed the following, all vacuum hose's that looked bad or worn I replaced. During this process I have checked the plugs burning pattern and have found a nice brown color to the plugs. There is no water in the oil or oil in the water. My charging system puts out a healthy 13.8 volts when running. Thanks for anyones time, I am out of ideas.