Stalling when temperature gauge is in the middle

After car is in the middle of the temperature gauge for a little bit, and running whether idling or driving it will stall. Does not have any codes. Sometimes it will restart but barely idles sputtering very badly, and if you depress the pedal it will pop and occasionally backfire in the exhaust. If I had to guess I would say a lean backfire as I don't smell a gas smell to induce a rich backfire. After cooling off it will restart fine and then do the same thing when it gets to operating temperature. Fuel pump? Fuel filter? Other parts that can cause these symptoms without popping a code? Please help!