Engine Warning Light

Hi all,

My 1.4 16v Elegance engine managment light came on after the other half topped up the oil, it stayed on for half a day and now has gone off and not come back on for a day. So Im a little confused by this, the other weird thing is that it only does it every few weeks the cars revs hunt whilst stationary if you lightly press the accelerator to 2 thousand rpm it stops it and the car is then fine and does not play up anymore for a couple of weeks. I have had the EGR Valve replaced and a servo pipe that was leaking. The light was reset when that was done and has stayed off till now. I have topped up the aircon and also the coolant as it was below the min mark and the other half said the the coolant temp light came on once before I topped it up, however the needle stayed in the middle so I have put it down to the low level and I have no leaks. All advice greatly accepted many thanks.