My mom as a 98 S70 and when it's cold it's takes several time to get it started if it starts. It turns over.. idles then dies. Ideas 🙏

 

Sounds like a weak fuel pump or fuel pump relay. I would start there and also do a full tune up if it has not had one in awhile.

 

The engine coolant temperature sensor is also a known issue with these. The car may think it's not cold. That doesn't easily set a check engine light/code as the temperature sensor doesn't have anything to benchmark against.

 

Very true. I have had two of these go bad in the past. One of the tell tale signs is if the temperature gauge moves toward a warm reading with a cold engine. The sensor is inexpensive and easy to replace. It is located right below the thermostat in the thermostat housing. Definitely a good place to start outside of a fuel delivery issue.

 

could also be the fuel pressure regulator allowing residual fuel pressure to bleed off. I'd probably start by testing out the ECT sensor (located under the thermostat cover). Cold resistance should be in the 2.5K range at 70F to 7K range at 32F. For a warm engine, the resistance drops under 300 ohms (say 200 ohms for a fully warmed up engine...). To test fuel pressure you can pop a gauge on the valve on the end of the fuel rail. A cold engine should keep some residual pressure (say 20 to 25 PSI) that should bump up to 40 PSI or so once the fuel pump engages. A quick trick would be to jumper the fuel pump relay to get it to turn on the pump before turning the key to build some residual pressure, then reinstall the relay and try to start the car.