94' S3 tach cutting out still

Hi,
Tach on my 94' S3 is cutting out again after I opened it up and cleaned the three mounting screw contacts as I saw pictures of the procedure here on the forum.
Closed it up again and same thing.
Anyone know what to do?Not sure if the plastic housing can take the prying action again to open it once more.
Could it be a bad ground also?

[trypcil]

How is the bike running, any stumbles at all? The #3 coil has a feedback loop associated to it that governs the tach. If the #3 coil is going south, the tach will either appear to fail or will become erratic. A clean of the spades on the coil may rectify the issue - good luck. :razz:

Cleaned and tightened all the contacts when I bought the bike last winter.
Running fine.
The tach works when it feels like it and when it does work sometimes the needle is lazy.

[trypcil]

this is a process of elimination, try swaping # 3 coil with another. :razz: