Can a vacuum leak cause multiple cylinder misfires and a lean code?
A vacuum leak lets unmetered air into the engine, causing a lean running condition like code P0171 and multiple cylinder misfires. This often happens alongside exhaust sputtering, and replacing basic ignition components like spark plugs and wires alone will not resolve the underlying air or fuel delivery issue.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1changing plugs and wires
- 2cleaning the MAF sensor
- 3cleaning plug threads and blocks with brake cleaner
- 4cleaning soot off spark plugs
- 5diagnosing under the hood instead of at the tail pipe
- 6looking for a shake that is out of time with everything else
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“hello, I have a Kia Ceed 2 2014 and I’ve just noticed a bit of a sputter at the exhaust does this sound like the start of a misfire?”source ↗
Kaylome97 · r/AskMechanics · 1 upvotes
Where this came up
People with this problem also raised
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