2.3L ('83-'97) Code 31 but no EGR!?? What do i do?

[Final777]

I have an 89 ranger 2.3 with a DIS engine. When i bought her she ran okay but she was missing the catalytic converter. To my knowledge this will affect power but isn't suppose to hurt the vehicle is driven. But after maybe a week or two of driving her she started hesitating and it was bad enough after a week or two later that i had to park her so that i did no more damage. If i floor she will sometimes get her power back and go forward but the entire time i am pushing on the accelerator she hesitates and jerks but it's not a violent jerk. I ran the codes on it and it said i have a code 31 (the same exact thing that has happened to my 86 ranger) but my 89 truck doesn't have an EGR on it there's just a plate on the back of the throttle body am I missing something? I'm not very familiar with DIS systems either please help!