What causes miss fires

[jimpy9]

What causes the engine to missfire??

 

[Foxspeed]

either a lack of spark or lack of fuel or a mechanical fault ie burnt valve

well thats the basics anyway!

mis-fire should be detected by the ecu and it should log a fault code

its all to do with complying with emission standards etc

 

[Troopy]

As above, I had a coil gone the other week and replaced all 4. Caused a misfire which the diagnostics showed was in cylinder 1 expensive but at least they're all done. Last time I changed 2 in my old Audi the other 2 went soon after.

 

[gaz]

I had a lambda issue on my previous 172 cup. Caused all sort if mis fire issues... Also 1 thing to check, I noticed my cup leakes through the washer jets if its rained right on to the rocker cover near plug 4 just make sure there's no moisture down there

 

[jimpy9]

would misfire cause bad fuling?
Ive replaced the Knock sensor and its still doing it a little dosent feel quiet as much but its still there