Car has trouble starting when damp and in the morning

My girlfired has a 2004 Volvo S40 and she tells my that when it rains or when there’s heavy fog it’s difficult to start the car. We live in a Southern California beach community where theres lots of fog and condensation in the AM, especially during cooler months. It sounds like there is a rumbling noise underneath the car, near the muffler or eshaust system. It hesitates when it starts, then when it does, it sometimes conks out. It sometimes doesn’t start for another 5 minutes. I think since the car has a good electrical system that the dampness near plugs and what not may not be the problem. Whats up with the rumbling or gurgling noise underneath? Please help because she’s making me nervous about it and who needs that during the holidays?!?!?!!

Has the Check Engine Light come on? In any case I would suggest it is likely two different issues.

The starting problem sounds like bad plug wires. If they are original, I would suggest replacing them, (I would likely do the plugs at the same time if they are original.)

The noise you are hearing is likely a heat shield or maybe a broken bracket or some other exhaust problem.

Neither of these should be expensive or difficult for someone to verify.

Thanks for your reply. No, the check engine light hasn’t come on. What else do think it could be. The noise underneatch is a gurgling noise. Can water or condensation get into the exhaust and disrupt the ignition? Fuel line? What do you think?

Moisture is disrupting something in the electrical system. As stated by joseph spark plug wires are a great place to look. Make sure all connections are secure, no wires have come loose with no cracked rubber, check also the coil and clean connections if necessary. In the old days if you tried to start it in the dark you could see a stray spark of even hear a spark going to ground instead of where it is supposed to go. The sound you hear is hopefully related to the starting problem, but after you get problem 1 fixed you can see if there is a problem 2.