i have a persistant missfireing problem with my vw polo mk2 breadvan the car is a 1987 1.3 mh engine with electonic ignition (hall sender type distibutor) every few months the problem returns and i find that either the distributor centre pin is stuck in or that one of the plug leads gone when i change either one which i find as gone the car runs fine again for another 4 to 5 months, the first signes of the fault reacurring is when the car goes up hill or when going slowly in second gear whch gradually get worst over a few weeks would anyone have any ideas as to what would cause this type of problem.

replace the cap and leads with top quality items ?

Steves right.

I'd guess the insulation is breaking down and you moving the parts around is enough to temporarilly resolve the issue.

If the brush in the Dist Cap is sticking - the cap is cheap/faulty/very old.

Eiterway round (and for any misfire problem) - fit quality leads, cap and arm (all consumable parts) before you start to look for the problem.

Ebay is not always your friend.....

yeah unless your really tight for money its worth searching out good quality parts , they will last longer so all good in the long run