high idle. Poor performance AGAIN!

[KiNK43]

Hi,
recently i have had trouble with my corsa 1.6 16v.
i will go back a few months when the problems started.
the idle used to hunt a little. (thaught nothing of it.)
then the idle got intermittently faster.
now sometimes it hunts, up and down, up and down!!! then just races off.
sometimes its fine! (but only for short spells really)
when the idle is fast the revs hang , for example... take foot off accelarator to change gear. revs stay high for 3-4 secs then drop. WEIRD!
makes driving all jerky.
have cleaned out idle control valve, seemed to fix problem but think it was just coincidence as problem returned next day.

then car cuts out. paperclip test says..... fuel pump... cam sensor... crank sensor...
does that mean that crank sensor failed first???
so i have cleaned both crank and cam sensors and checked connections. it hasnt cut out since but it feels like its pulling a ton! very little power off the line.

sorry for the long post but i have tried to research the problems and my i am losing my mind! (so many sensors all over these engines!)
i could really do with some advice as where to start first.

thanks for any help.