Look for a vacuum leak.
It would greatly depend on the source of the leak, need more info.
I am having a stalling problem and I heard it can be the cause of a vacuum leak and if that is true how can i fix it and where is it at?
Need to know the location of the vacuum leak in order to answer this.
It depends on where the leak is. If it's just a hose that is pretty easy to fix. If it is the manifold gasket that is a bit harder and can be expensive. Either way you need to get it taken care of soon because your car will not perform at it's best with a vacuum leak and gas mileage will probably be poor as well.
Fix it.
You have to determine the source of the leak then decide on how to fix it.
You cant
You have to find the leak in the system. Once your entire vacuum system holds constant suction, the pump will cut off and only come on when needed.
First you have to locate the source of the vacuum leak then you can determine what steps to take to stop the leak. Determine the source and re-post your question with more info.
Air vents in most cars are vacuum controlled. Check for vacuum leaks in any part of the engine system. Also check the ac/heat control system, as they can develop a vacuum leak with time.
fix the vacuum leak