Vacuum ... the servo assistance on the brakes works by creating a vacuum from the inlet manifold. So as your idle increases, the vacuum increases .. and sucks on the servo ... and your pedal moves as it is attached.
So I'm either a genius or talking out of my backside again!
On the idling problem it might be the IDLE ACTUATOR on the side of the throttle. If you move the butterfly manually, this can get out of sync and tries to open/close the butterfly at the wrong time. And this is likely to happen when you cleaned the throttle. I think this is the main cause of all the idle problems esp the kangaroo-ing when you lift off the gas.
With the bonnet open, turn off the ignition, and listen carefully. You might hear the actuator resetting .. sort of whirr-click a couple of times coming from the throttle.
Try getting it reset (needs a diagnostic system) or it might work if take if off and replace it HOLDING the butterfly SHUT. That way you are making it go back to the correct idle position.
You need to take the throttle body off and turn it anti-clockwise through 90 degrees to see it. Remove the three bolts holding it to the throttle then put it back but hold the butterfly shut. Then put the throttle body back WITHOUT touching the throttle cable or moving the butterfly again. Can't guarantee this will work, and you may still need to get it on a diag system, but worth a try.