2000 Jeep Cherokee Temperature Gauge

I have a 2000 Jeep Cherokee Sport. It has 146k miles. Car runs great but when temperature gauge goes over 210, and I cut it off (like when I am running errands, running in and out of the store), when I turn it back on, car struggles to turn on. But it will turn on. The gauge NEVER goes but slightly over 210, never in the red where it overheats. On the highway, it's fine. City driving is when it occurs. Also, when it sits in the sun, and I try to cut it on like last week when it was 80 degrees, the car struggled to start. Sometimes check gauge light comes on quickly and goes off. Any ideas?

Thanks!