Why car having cranking issues?

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! Cranking issues without warning lights can be tricky. If the battery, alternator, and starter check out, the fuel system could definitely be the culprit. A clogged fuel filter could restrict fuel flow, causing hard starts, especially first thing in the morning when the system is cold. That rumbling noise you mentioned might hint at a fuel pressure issue or even an exhaust leak. And the noise when you turn it off? Could be your engine cooling down or a vacuum leak. I'd also consider checking for any loose engine mounts while you're at it. If you need any further advice or want help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554.