My car will start right up no sounds but will die after 30 mins of idling

It’s a 1998 saab 900 s 2.3 L car was maintenanced regularly until 2019 which it sat until I bought it a couple months ago. The car is in great condition. When I start the car it turns on perfectly no sounds no anything, after about half an hour the car will die and wont start again until left for awhile. Then it will start up perfectly and die again. I got the fuel pump checked and it’s not the pump.. I’m not sure what else it could be. Please help.