Why won't 1994 ls 400 pull off until it warm up

There could be a number of reasons. Does the car smoke? Are any warning lights on? Does the car shift properly? I would need more information in order to best advise you.

This is when I first crank up the car and yes it smoke for a little while and then it quite smoking but rpm gauge fluctuate until it warms up and then it will pull off but sluggish

Ok. What color is the smoke? White? Blue? Black? This will help narrow down the issue as the color of the smoke can tell you which part has failed. Let me know.

The smoke is white and smell like gas

One of the main causes of white exhaust smoke and coolant loss is a cracked or warped cylinder head, a cracked engine block, or head gasket failure caused by overheating. A cracked head may allow coolant to leak into one or more cylinders or into the combustion chamber of the engine. I would avoid driving it and have it towed to a shop for confirmation but Im almost certain its the head gasket.

I am not losing coolant nor is water running out of tail pipe car do not smoke while driving heater work fine can drive all day and no smoke

Only when I first crank the car

I understand. The crack can occur causing the coolant to leak into the engine (including the cylinders). This will cause the coolant to burn off after the car is warm, hence why it doesn't smoke when the care is driving and warmed up. I stick by my original diagnosis that is is most likely a blow head gasket.