when the weather is cold the van starts right up but runs rough. When you accelerate or go uphill there is a loud knock from the left side of the engine.
Once it warms up it seems to run fine sometimes a slight left side engine knock. What do you think it could be? Maybe a sensor?

when the weather is cold the van starts right up but runs rough. When you accelerate or go uphill there is a loud knock from the left side of the engine.
Once it warms up it seems to run fine sometimes a slight left side engine knock. What do you think it could be? Maybe a sensor?

Sounds like you may need a rebuild.

Sensor? Does your check engine light work? Can you pull codes?