Cylinder misfire and white smoke from exhaust
An engine misfire persisting on the same cylinder despite replacing spark plugs and checking coils, combined with white exhaust smoke, typically indicates coolant entering the combustion chamber. This can foul the spark plug and lead to ongoing misfires and smoke.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Replacing spark plugsDid this help you?
- 2Checking coilsDid this help you?
- 3Taking the vehicle to a professionalDid this help you?
- 4draining the incorrect fluid from the engineDid this help you?
- 5checking for exhaust leaksDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Misfiring on cylinder one, replaced all the spark plugs 6 months ago, all the coils are fine. Misfiring again on cylinder one checked the coils. Pulled the spark plug and it was filthy and black. Replaced it. Still misfiring, but now I also have white smoke coming out the exhaust.”source ↗
“I put some 2 stroke oil inside as a mistake(I didn’t switch it on I realised immediately) and completely drained it before putting the 4stroke back. Could this be the issue? I’m supposed to drive 3 hours tomorrow; Am I going to have a bad surprise?”source ↗
“I was asking because I had a problem 2 days ago after work I started the car and it smoked a blue smoke after 1-2 mins and it went away after 30 Seconds but didn’t happen since so I’m confused on what’s was that all about”source ↗
Where this came up
People with this problem also raised
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- 2Why is my car blowing oil smoke from the exhaust at startup?