2nissan240sx

Hello all, I am a noob to this forum. I have a 90 s13 body with a 92 ka24de and a manual tranny. I am having problems with the idle. With the idle adjustment screw in more than half way in, when the car is cold it will start for a few seconds and then die, unless I give it gas. (Know that I am in an area that is still in the 70s at night in November.) It also wants to stall when I come to a stop. At least until it warms to normal operating temp. When warm it is fine. I have noticed though that if the screw is more than 3/4 open, it doesn't do any of this. Also when I disconnect the tps harness and try to adjust the idle, it will not adjust below like 900 rpms. So what do I want to know? I would like to know if it would be ok to drive the car with the screw open like that? I have heard that if you do that it could hurt the engine internally. Is this true and if so what can it do? If I can't drive like that, what would be my best route to fix the problem? Thank you for any help that you can give me.