If the car never gets up to temp then it never goes closed loop right?

Problem 1.
The reason i ask is because when the car heats up it will bounce idle from 500 to 1000 and lets say i just stepped on it and revs are coming down with clutch in from 3500 or higher the car will just die.
IT doesnt run o2 tho thats wat i think it is but i havent bin able to find the cables since i bought the car. Would that cause my problem? but i was thinking the if i unplug the temp sensor the ecu will never kno the car is a op temp and wont try to read the o2


I apriciate any help thanks