supra running rough

[finn]

I Just bought an 86 supra, non-turbo automatic, and It ran great for a month after I bought it. Recently It has been running rough If I start it when it's already warm, and doesn't even out after driving it for 30 min. it still drives but doesn't have as much power when it's running like that. In them mornings, starting it cold, it takes about a second longer to start but runs even and smooth, completely different from when it's running rough. Does anyone have any clues as to what is causing this, and should I even be driving it if it is acting like this? - also, I put in injector cleaner today to see if it would help, haven't driven it enough to tell if it is.

any ideas would be appreciated

-Finn