It's possible that the cold start enrichment is too much gas for what the isc will let thru, and needs the fidle valve air to lean it out enough to not trigger the ohtwo light. If so, warmer weather may provide a warm weather cure. Or you might try the spark plug spacer trick under the ohtwo sensor that they use for the rear sensor on two sensor obd2 cars.

Mud, you seem to have a dead spot in the tps rheostat. Hook an ohmeter up to it and see if you can see the dead spot as you move the throttle.

Not responsible for advice not taken...