Cadman11,
You might want to check this site out and maybe ask them. I hear that is a known problem with Elect. pick-up and some people have shared their fixes. You don't mention the ones You have.
Might be worth it to You:
http://www.newrailwaymodellers.co.uk/Forums/viewforum.php?f=1&sid=abf41292e780014383deb84944bdbfe8
Good Luck!
Frank
I have several OO scale Hornby and Heljan diesel loco models and am disappointed with the bad electrical wheel pickups. Does anyone have suggestions for fixing this horrible setup? Worse with a DCC decoder as the power is contantly cutting in and out. I've cleaned the pickups and back of wheel surface but no change.
Thanks in advance