Why does my car misfire when it rains?
Moisture gets into components like the ignition system, distributor cap, battery, and coil during wet weather, causing the car to struggle to start or misfire badly when accelerated. Drivers are left stranded with a vehicle that won't turn over or hesitates heavily until everything dries out.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Spraying WD-40 on the distributor cap to temporarily dry or displace moisture
- 2Waiting for the engine and electrical components to dry out naturally
- 3Using a jumper box
- 4Checking the battery, coil, and seals
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“every time it rains it misfires specially when I floor it”source ↗
“the car refused to start, he took the distributor cap off and sprayed some WD-40 then the car started, but still misfired when I floored”source ↗
“I am going to get under the hood and work on the battery and coil, but first I just need to get it started, and even with a jumper box, the car is struggling to do so, so I was wondering if simply waiting for it to dry out is an option, and if so about how long should it take?”source ↗
“It started just fine this morning, but it rained on my way to work.”source ↗
Where this came up
People with this problem also raised
- 2Is it safe to drive a car with front-end damage in heavy rain?
- 4Why is my car misfiring and stalling after changing spark plugs?
- 2Why is my car making a weird noise after driving through water?
- 17Why does my car engine cut out after driving for a while?
- 19Engine misfires and RPM surging when driving uphill
- 3Cylinder misfire and white smoke from exhaust