I have just replaced the dizzy cap, rotor arm, points and HT leads on my 2.25 S3. Around about the same time I replaced the manifold to head gasket and the inlet to outlet manifold gasket where the stove is.
However it sometimes seems to be running rough at idle. It will run fine for a few seconds, then a little rough. If you use the footbrake while it is running rough, its enough to kill the engine. It runs fine at higher revs - pulls normally.
I have turned up the idle speed a little but its still won't idle smoothly. I checked the gap today and altered it ever so slightly, but not change. I tried a technique I saw once of pulling a HT lead off and holding it with a screw driver near an earth. The varied between orange and bluey orange.
I read on other posts about greese on the breakers when new, but its done about 80 miles since so it should have burned off?
I also wondered about carb freezing - I did observe a little ice forming on the lower butterfly valve...
Any ideas? Cheers, GDL.