So I’ve been having issues with a 2010 Volkswagen Jetta. The battery continues to drain when it’s not being driven and the car has to crank longer than usual before starting. Once the car starts though it runs fine. I have tried using a new battery as well.
The electronic systems that are running “in the background” on all modern cars will result in some depletion of the battery’s charge while it is parked. However, we don’t know how much your battery is being depleted, so there is also a chance that you have a parasitic electrical drain taking place, and only a good mechanic can determine that for you.
This could indicate a need for spark plug replacement, or it could be an indication of a fuel supply problem.
I think you have two separate issues that need the attention of a skilled mechanic.
I suggest that you seek an independent VW specialist in your area.
This very well may be so, but I think the parsitic draw should be addressed first. Once that is fixed and the car is equipped with a healthy and charged battery, the starting problem may disappear. It might be struggling to start because the battery is not fully charged.