Mr. White

You can check the first three by swapping them around. It could be a fowled plug, but it is common to have to replace the ignition control module. If you have further questions about it or how to trouble shoot it, let me know. I can give you a hand. I had the same problem with mine a while back.

David...

inbetweener

or maybe the classic dirty injectors?<ul><li><a href="http://search.audiworld.com/index.mhtml?q=ignition+amplifier&amp;wf=022210&amp ;cat=010201&amp;dt=range&amp;db=01%2F01%2F2003&amp ;de=08%2F15%2F2003">Click</a></li></ul>

drwombat

I just felt like posting this bimmer sandwich picture, and didn't feel like starting my own thread.

Just to be different.

Nothing like two gorgeous A4s to corral in one aberrant bimmer...

<img src="http://www.drwombat.com/files/sandwich.jpg">

Kris Hansen

HG is quite unlikely.

ArandA4

is incorporated into the coil pack module where the spark plug wires are connected.

As for diagnosing... maybe try swapping plugs and see if the misfire relocates. Else it's probably a dirty injector or a bad coil.

Famous Mortimer

Could also be a bad plug or plug wire. You don't have a coilpacks, you have just one big ignition coil, which could be an issue but that's rare.

Žob

Plug wire and or plug.