Ever since my engine overheated yesterday( Messed up coolant refilling) I have this check engine light that comes on when i idle and whenever i add gas! The engine splutters and sometimes just dies. Could this problem be my battery? Or spark plugs? I drove from houston to austin and this problem gradually grew worse... Sometimes my engine light, oil and battery light turns on the same time.

does your engine spin over at normal speed when you turn the key to start ?