Engine management light appears and disappears sometimes

So a few months back my car started showing an engine management light so we changed the coil pack and spark plugs. Now after a few months the car has started showing the same engine light and the car starts losing power then turns off. But after a few minutes it works as normal. i just want to know is there anything wrong? My dad also says he has noticed the water getting empty in the coolant tank quicker. So just wanted an expert opinion on what i can do to check what i can do to solve this issue?