My torque converter locks in for a few minutes then kicks out for few seconds then locks back again. The process repeats over and over. I has 1985 305 four barrel carb.I have replaced the temp sensor at thermostat housing with no change. Any ideas?

 

What about the pressure switch in the trans? The temperature switch in the trans? Is the brake pedal switch going off intermittently?

Study the circuit, and all the items involved, them perform a methodical diagnosis.