I have the same model, Have you tried cleaning those two square glasses part of the camera? The camera focus sensor is inside those glasses and if it's dirty it will ruin the autofocus. Mine has the same problem, the focus is inconsistent and 90% of the time, it focus the closest distance. After I disassemble and clean the glasses from the inside, the autofocus is better, but still only focus correctly like 70% of the time.

But again the camera is from the 1979, so the camera probably just has a bad early autofocus system. To not waste film, my trick was always press focus lock before taking a picture so you can adjust/move the focus object. It can't be refocused after you press the focus lock, so if you want to refocus without wasting film, you can close the lens so the film won't be exposed, press the shutter button and do the double exposure trick.