ok lads my 1989 2wd sapphire cosworth wont stay running.it will start up and idle fine at first then after about 2 minutes it will hunt up to 2000rpm and stay for 3 seconds and then back to normal idle,then after 10 minutes or so of sitting fine on idle it will cut out and wont start back up unless i leave it for 5 minutes or so.

it has my heaed all over the place i have cleaned out the throttle boddie and idle control valve and mad sure all the vacums are in the right places.

any ideas on what it could be ?