Buick, service engine one when key in but disappears when car running

That's the way it works, the other lights turn on then go off as a circuit check but the check engine light stays on until it starts because if there's a problem with the engine control it will remain on until repaired. I hope this helps. Take care.

Thank you for your answer. I'm not sure I understand does that mean there's an issue and o should have it checked? Last time it was on it would stay on all the time.