UK Car Repair: astra missfire, electronic unit, difficult questions

Question
every couple of months my 1997 1600 8v astra will start to missfire at lo revs,its ok above 2000rpm.I suspected moisture so have tried spraying the ignition.this never cures it strait away but usualy two days later it cures it self.any ideas  

Answer
These are difficult questions to answer. Clearly if it is a recurring fault there is a bad connection somewhere. It is most likely in an electronic unit. To start with I would remove all electrical connectors and make sure they are clean and dry. Other than that you may have to wait until the fault worsens to a point where it can be traced.