just read a page on fordmods.com and someone in there fixed the problem by just disconnecting the ISC and adjusting the idle via the screw on the throttle body......... is there any harm in doing that other than idle won't adjust for ac etc....?

if this won't hurt anything I'm tempted to try it for a temporary fix

yeh its called reseting your base idle.

purchase of a max elery or gregorys workshop manual pays in the end when diagnosing problems.

True dat.

Sorry I probably should have mentioned that I know how to do it, just wasn't sure if it would do any damage (i know sfa about ecu's etc....)
I've done it anyway, just unplugged the harness and adjusted the idle manually, works beautifully, revs don't hang and idle's properly. sadly no cackle when engine braking though stupid exhaust with two mufflers *shake fist* ) tempted to now switch the exhaust with the one on the ED. Therefore proving manta > walker