Does anyone have any idea as to what causes the tick over needle to fluctuate. I have cleaned the i c v, put new leads, plugs and fuel filter on. The car is a 1998 bog standard 60,000 mile manual turbo ep91. The only thing i have not changed is the dizzy cap and rotor arm which i have just ordered from camskill. When i pull the plug on the i c v there is no change in the idleing does this mean it's nacked because it is starting to do my nut right in