The idle on the XG has started to play up

When the a/c kicks in the engine will speed up to over 1000rpm and you need to hold it on the brake. It will return to normal when you blip the throttle

If I'm sitting in traffic for a while the idle speed drops below 500rpm and the engine starts to idle roughly. Again it returns to normal if I blip the throttle

Any suggestions please

check the idle controll solonoid and the tps for a start and see how ya go does it do it all the time?