2013 VW Jetta won't start after rain?

So sometimes my Jetta chugs and chugs but won’t start. The chugging is steady and does not die down or stop. There are no other noises than the chugging. If I wait anywhere from a few minutes to half an hour, the car starts with no problem. A few minutes wouldn’t bother me if I knew it would start, but waiting up to half hour is suspensful and frustrating. (I don’t try it every few minutes. I try it a couple of times and on two occasions I had to call AAA and then tried it several minutes or half an hour later and had to cancel AAA. Now I know not to call AAA.)

This happened 3 or 4 times. Each time it had rained most of the day. The garage doesn’t know what it could be. I read that moisture can affect the distributor cap and the spark plug wire insulation. Woud they have checked this? I also recall once I had a car that got moisture on the manifold but I forget if it wouldn’t start or stalled or what.

The only OBD code says P0440, which means a leak in the fuel tank vapor system or a vapor pressure sensor has malfunctioned.

Any ideas?

This is generally caused by shorting out the secondary ignition due to moisture in the air. True of any car no matter if it has a distributor, coil packs, or COPs.

Keep a can of WD-40 with you and when it happens spray the engine coils down with it.

Next time you change the spark plugs liberally coat the inside and outside of the coil boots with an electrolytic grease. Those things should cure the problem. Keep in mind that WD in the 40 part stands for water displacement.

I have the same problem with my distributor GMC Sonoma at times. An old Mercury I had did not suffer from this because it had a factory rubber boot that fit around the distributor and that held the moisture at bay to some extent. Hope that helps.