If you pick the revs up does it miss
It sounds like the Phase sencor in the dizzy mine started doing that then packed up all together found out it was all down to the phase sencor

Also a m8s cossie developed the same sort of thing started missing and check it shame again PHASE SENCOR

EASY WAY TO FIND OUT ; Remover the Dizzy cap remove the Rotor arm and plastic dust cover (if its still on there should be but some arent) and your see 2 Wires going to a half moon thingy basicly if is fcuked the wires will be bare and look all manky

Its easy to remove 2 srews and unplug the wires its abit fiddlery but not hard

Here you go Heres the link to Stu's Ebay shop this is whot it should look like (wires should be covered )
http://cgi.ebay.co.uk/Distributor-ph...QQcmdZViewItem