Reading through forum to try and cure rough tickover decided to take out cam solenoids assuming that they may not work properly causing rough idle. Reply from my last post suggested oil change might sort it out hence checking for crud in solenoids. Fine mesh strainer looked a bit sludged up so cleaned out but expected that I should be able to move the spring loaded plunger bit inside that you can see on end. this not the case. Should this element inside body slide in and out against the spring you can see? Strange that put them back and idle now normal, guess just sludge preventing oil pressure getting to solenoid. Still want to know how they work and what they do, assume oil pressure changes and alters cam timing a bit?. Anyone?