What is the cause of a misfire?

I had one and my brother had to replace a cyliner.

What could it be? Very fast accelaration?

 

plugs, wires, ignition timing?

 

injector could be totaly clogged, that would cause a misfire...which is when a cylinder doesnt complete its job. So a totally blocked off injector could be minimizing the fuel goin into it and not getting enough gas to combust fully. Find a VAGcom or take it to a dealer, it will tell you if it is a misfire and which cylinder (if u dont kno it is a misfire for sure)

EDIT: i worked on a f150 at my shop with a misfire in cyl 5. could be all of the things sandman said plus injectors. Like we replaced the wire on it, still missfired, then replaced the injector and it worked. plugwire, plug, or injector is ur best bet.

 

What about throttle body issues? Couldn't that also cause a misfire?

 

anything that would cause an incomplete combustion can lead to missfires. anything to do with air, fuel, and spark.

 

Cracked, leaking intake mainfold, could have a leak at the TB - intake connection. Bad coilpacks, plugs, dirty injectors, the list can go on.

 

couldnt he put in a few bottles of fuel system cleaner, like gumout regane or lucas oil cleaner.