Is it normal for a torque converter not to lockup untill the engine is warmed up?

I have a 2000 plymouth neon and ive had some weird things going on the im lost on. When i first start the car up and go to pull out of the drive way it shifts fine. As i go down the road i noticed it stays in third gear which i would ume after 40 mph the torque converter would lock up as i usually would but until i see the needle for the engine Temperature move it wont lock up. Another weird thing is when im going down the road and give it some gas to speed up while its locked up i noticed a random jumping and bucking as like the car is out of tune which i know its not the other gears have no similar problems. also it gets worse when i turn the lights on. anyone have any ideas?